diff --git a/.pre-commit-config.yaml b/.pre-commit-config.yaml
index d1748493..31d9d64c 100644
--- a/.pre-commit-config.yaml
+++ b/.pre-commit-config.yaml
@@ -23,3 +23,8 @@ repos:
     hooks:
       - id: hacking
         additional_dependencies: []
+  - repo: https://github.com/asottile/pyupgrade
+    rev: v3.18.0
+    hooks:
+      - id: pyupgrade
+        args: [--py3-only]
diff --git a/doc/source/conf.py b/doc/source/conf.py
index 1a6afbc4..75d5cd80 100644
--- a/doc/source/conf.py
+++ b/doc/source/conf.py
@@ -1,4 +1,3 @@
-# -*- coding: utf-8 -*-
 # Licensed under the Apache License, Version 2.0 (the "License"); you may
 # not use this file except in compliance with the License. You may obtain
 # a copy of the License at
diff --git a/doc/source/ext/gen_ref.py b/doc/source/ext/gen_ref.py
index a5071887..3886aba0 100644
--- a/doc/source/ext/gen_ref.py
+++ b/doc/source/ext/gen_ref.py
@@ -1,4 +1,3 @@
-# -*- coding: utf-8 -*-
 # Licensed under the Apache License, Version 2.0 (the "License"); you may
 # not use this file except in compliance with the License. You may obtain
 # a copy of the License at
@@ -25,7 +24,7 @@ def gen_ref(ver, title, names):
     refdir = os.path.join(BASE_DIR, "ref")
     pkg = "heatclient"
     if ver:
-        pkg = "%s.%s" % (pkg, ver)
+        pkg = "{}.{}".format(pkg, ver)
         refdir = os.path.join(refdir, ver)
     if not os.path.exists(refdir):
         os.makedirs(refdir)
diff --git a/heatclient/common/base.py b/heatclient/common/base.py
index 550a77a6..2ec763e5 100644
--- a/heatclient/common/base.py
+++ b/heatclient/common/base.py
@@ -48,7 +48,7 @@ def getid(obj):
 
 
 # TODO(aababilov): call run_hooks() in HookableMixin's child classes
-class HookableMixin(object):
+class HookableMixin:
     """Mixin so classes can register and run hooks."""
     _hooks_map = {}
 
@@ -92,7 +92,7 @@ class BaseManager(HookableMixin):
 
         :param client: instance of BaseClient descendant for HTTP requests
         """
-        super(BaseManager, self).__init__()
+        super().__init__()
         self.client = client
 
     def _list(self, url, response_key=None, obj_class=None, json=None):
@@ -279,13 +279,12 @@ class CrudManager(BaseManager):
         :param base_url: if provided, the generated URL will be appended to it
         """
         url = base_url if base_url is not None else ''
-
-        url += '/%s' % self.collection_key
+        url = '/'.join([url, self.collection_key])
 
         # do we have a specific entity?
-        entity_id = kwargs.get('%s_id' % self.key)
+        entity_id = kwargs.get('{}_id'.format(self.key))
         if entity_id is not None:
-            url += '/%s' % entity_id
+            url = '/'.join([url, entity_id])
 
         return url
 
@@ -297,7 +296,7 @@ class CrudManager(BaseManager):
             else:
                 if isinstance(ref, Resource):
                     kwargs.pop(key)
-                    kwargs['%s_id' % key] = getid(ref)
+                    kwargs['{}_id'.firmat(key)] = getid(ref)
         return kwargs
 
     def create(self, **kwargs):
@@ -323,12 +322,13 @@ class CrudManager(BaseManager):
         :param base_url: if provided, the generated URL will be appended to it
         """
         kwargs = self._filter_kwargs(kwargs)
+        query = '?{}'.format(parse.urlencode(kwargs)) if kwargs else ''
 
         return self._list(
-            '%(base_url)s%(query)s' % {
-                'base_url': self.build_url(base_url=base_url, **kwargs),
-                'query': '?%s' % parse.urlencode(kwargs) if kwargs else '',
-            },
+            '{base_url}{query}'.format(
+                base_url=self.build_url(base_url=base_url, **kwargs),
+                query=query,
+            ),
             self.collection_key)
 
     def put(self, base_url=None, **kwargs):
@@ -343,7 +343,7 @@ class CrudManager(BaseManager):
     def update(self, **kwargs):
         kwargs = self._filter_kwargs(kwargs)
         params = kwargs.copy()
-        params.pop('%s_id' % self.key)
+        params.pop('{}_id'.format(self.key))
 
         return self._patch(
             self.build_url(**kwargs),
@@ -362,12 +362,13 @@ class CrudManager(BaseManager):
         :param base_url: if provided, the generated URL will be appended to it
         """
         kwargs = self._filter_kwargs(kwargs)
+        query = '?{}'.format(parse.urlencode(kwargs)) if kwargs else ''
 
         rl = self._list(
-            '%(base_url)s%(query)s' % {
-                'base_url': self.build_url(base_url=base_url, **kwargs),
-                'query': '?%s' % parse.urlencode(kwargs) if kwargs else '',
-            },
+            '{base_url}{query}'.format(
+                base_url=self.build_url(base_url=base_url, **kwargs),
+                query=query,
+            ),
             self.collection_key)
         num = len(rl)
 
@@ -390,7 +391,7 @@ class Extension(HookableMixin):
     manager_class = None
 
     def __init__(self, name, module):
-        super(Extension, self).__init__()
+        super().__init__()
         self.name = name
         self.module = module
         self._parse_extension_module()
@@ -408,10 +409,10 @@ class Extension(HookableMixin):
                     pass
 
     def __repr__(self):
-        return "<Extension '%s'>" % self.name
+        return "<Extension '{}'>".format(self.name)
 
 
-class Resource(object):
+class Resource:
     """Base class for OpenStack resources (tenant, user, etc.).
 
     This is pretty much just a bag for attributes.
@@ -435,9 +436,9 @@ class Resource(object):
         reprkeys = sorted(k
                           for k in self.__dict__
                           if k[0] != '_' and k != 'manager')
-        info = ", ".join("%s=%s" % (k, getattr(self, k)) for k in reprkeys)
+        info = ", ".join("{}={}".format(k, getattr(self, k)) for k in reprkeys)
         class_name = reflection.get_class_name(self, fully_qualified=False)
-        return "<%s %s>" % (class_name, info)
+        return "<{} {}>".format(class_name, info)
 
     @property
     def human_id(self):
diff --git a/heatclient/common/deployment_utils.py b/heatclient/common/deployment_utils.py
index 80a9f7de..05e813d9 100644
--- a/heatclient/common/deployment_utils.py
+++ b/heatclient/common/deployment_utils.py
@@ -93,8 +93,8 @@ def build_derived_config_params(action, source, name, input_values,
 
 def create_temp_url(swift_client, name, timeout, container=None):
 
-    container = container or '%(name)s-%(uuid)s' % {
-        'name': name, 'uuid': uuid.uuid4()}
+    container = container or '{name}-{uuid}'.format(
+        name=name, uuid=uuid.uuid4())
     object_name = str(uuid.uuid4())
 
     swift_client.put_container(container)
@@ -105,12 +105,12 @@ def create_temp_url(swift_client, name, timeout, container=None):
 
     key = swift_client.head_account()[key_header]
     project_path = swift_client.url.split('/')[-1]
-    path = '/v1/%s/%s/%s' % (project_path, container, object_name)
+    path = '/v1/{}/{}/{}'.format(project_path, container, object_name)
     timeout_secs = timeout * 60
     tempurl = swiftclient_utils.generate_temp_url(path, timeout_secs, key,
                                                   'PUT')
     sw_url = urlparse.urlparse(swift_client.url)
-    put_url = '%s://%s%s' % (sw_url.scheme, sw_url.netloc, tempurl)
+    put_url = '{}://{}{}'.format(sw_url.scheme, sw_url.netloc, tempurl)
     swift_client.put_object(container, object_name, '')
     return put_url
 
diff --git a/heatclient/common/event_utils.py b/heatclient/common/event_utils.py
index 93d424cc..24b636d6 100644
--- a/heatclient/common/event_utils.py
+++ b/heatclient/common/event_utils.py
@@ -251,8 +251,8 @@ def wait_for_events(ws, stack_name, out=None):
         event = events_mod.Event(None, data['payload'], True)
         # Keep compatibility with the HTTP API
         event.event_time = data['timestamp']
-        event.resource_status = '%s_%s' % (event.resource_action,
-                                           event.resource_status)
+        event.resource_status = '{}_{}'.format(event.resource_action,
+                                               event.resource_status)
         events_log = utils.event_log_formatter([event], event_log_context)
         out.write(events_log)
         out.write('\n')
@@ -261,4 +261,4 @@ def wait_for_events(ws, stack_name, out=None):
             if stack_status in ('COMPLETE', 'FAILED'):
                 msg = msg_template % dict(
                     name=stack_name, status=event.resource_status)
-                return '%s_%s' % (event.resource_action, stack_status), msg
+                return '{}_{}'.format(event.resource_action, stack_status), msg
diff --git a/heatclient/common/format_utils.py b/heatclient/common/format_utils.py
index 598ae9eb..db43a98f 100644
--- a/heatclient/common/format_utils.py
+++ b/heatclient/common/format_utils.py
@@ -90,6 +90,6 @@ def print_software_deployment_output(data, name, out=sys.stdout, long=False):
             truncate=not long,
             truncate_prefix='...',
             truncate_postfix='(truncated, view all with --long)')
-        out.write('  %s: |\n%s\n' % (name, output))
+        out.write('  {}: |\n{}\n'.format(name, output))
     else:
-        out.write('  %s: %s\n' % (name, data.get(name)))
+        out.write('  {}: {}\n'.format(name, data.get(name)))
diff --git a/heatclient/common/http.py b/heatclient/common/http.py
index f71ca668..af3d7d9e 100644
--- a/heatclient/common/http.py
+++ b/heatclient/common/http.py
@@ -68,7 +68,7 @@ def get_system_ca_file():
     LOG.warning("System ca file could not be found.")
 
 
-class HTTPClient(object):
+class HTTPClient:
 
     def __init__(self, endpoint, **kwargs):
         self.endpoint = endpoint
@@ -146,7 +146,7 @@ class HTTPClient(object):
     def log_http_response(resp):
         status = (resp.raw.version / 10.0, resp.status_code, resp.reason)
         dump = ['\nHTTP/%.1f %s %s' % status]
-        dump.extend(['%s: %s' % (k, v) for k, v in resp.headers.items()])
+        dump.extend(['{}: {}'.format(k, v) for k, v in resp.headers.items()])
         dump.append('')
         if resp.content:
             content = resp.content
@@ -216,7 +216,7 @@ class HTTPClient(object):
             message = (_("Error finding address for %(url)s: %(e)s") %
                        {'url': self.endpoint_url + url, 'e': e})
             raise exc.InvalidEndpoint(message=message)
-        except (socket.error, socket.timeout) as e:
+        except (OSError, socket.timeout) as e:
             endpoint = self.endpoint
             message = (_("Error communicating with %(endpoint)s %(e)s") %
                        {'endpoint': endpoint, 'e': e})
@@ -313,7 +313,7 @@ class SessionClient(adapter.LegacyJsonAdapter):
         if 'data' in kwargs:
             kwargs['data'] = jsonutils.dumps(kwargs['data'])
 
-        resp, body = super(SessionClient, self).request(
+        resp, body = super().request(
             url, method,
             raise_exc=False,
             **kwargs)
diff --git a/heatclient/common/resource_formatter.py b/heatclient/common/resource_formatter.py
index 0d56d915..0e49a548 100644
--- a/heatclient/common/resource_formatter.py
+++ b/heatclient/common/resource_formatter.py
@@ -17,7 +17,7 @@ import hashlib
 from cliff.formatters import base
 
 
-class ResourceDotInfo(object):
+class ResourceDotInfo:
 
     def __init__(self, res):
         self.resource = res
@@ -34,7 +34,7 @@ class ResourceDotInfo(object):
         if not prefix:
             prefix = 'r'
         hash_object = hashlib.sha256(url.encode('utf-8'))
-        return '%s_%s' % (prefix, hash_object.hexdigest()[:20])
+        return '{}_{}'.format(prefix, hash_object.hexdigest()[:20])
 
 
 class ResourceDotFormatter(base.ListFormatter):
@@ -46,7 +46,7 @@ class ResourceDotFormatter(base.ListFormatter):
         writer.write()
 
 
-class ResourceDotWriter(object):
+class ResourceDotWriter:
 
     def __init__(self, data, stdout):
         self.resources_by_stack = collections.defaultdict(
diff --git a/heatclient/common/utils.py b/heatclient/common/utils.py
index 61c77830..59403fe3 100644
--- a/heatclient/common/utils.py
+++ b/heatclient/common/utils.py
@@ -128,7 +128,7 @@ def print_list(objs, fields, formatters=None, sortby_index=0,
 def link_formatter(links):
     def format_link(link):
         if 'rel' in link:
-            return "%s (%s)" % (link.get('href', ''), link.get('rel', ''))
+            return "{} ({})".format(link.get('href', ''), link.get('rel', ''))
         else:
             return "%s" % (link.get('href', ''))
     return '\n'.join(format_link(link) for link in links or [])
@@ -174,7 +174,7 @@ def print_dict(d, formatters=None):
     print(pt.get_string(sortby='Property'))
 
 
-class EventLogContext(object):
+class EventLogContext:
 
     def __init__(self):
         # key is a stack id or the name of the nested stack, value is a tuple
diff --git a/heatclient/exc.py b/heatclient/exc.py
index e3ac2f97..5cbd915b 100644
--- a/heatclient/exc.py
+++ b/heatclient/exc.py
@@ -46,7 +46,7 @@ class HTTPException(BaseException):
     code = 'N/A'
 
     def __init__(self, message=None, code=None):
-        super(HTTPException, self).__init__(message)
+        super().__init__(message)
         try:
             self.error = jsonutils.loads(message)
             if 'error' not in self.error:
diff --git a/heatclient/osc/v1/build_info.py b/heatclient/osc/v1/build_info.py
index 1ab39dfb..6428fe42 100644
--- a/heatclient/osc/v1/build_info.py
+++ b/heatclient/osc/v1/build_info.py
@@ -27,7 +27,7 @@ class BuildInfo(command.ShowOne):
     log = logging.getLogger(__name__ + ".BuildInfo")
 
     def get_parser(self, prog_name):
-        parser = super(BuildInfo, self).get_parser(prog_name)
+        parser = super().get_parser(prog_name)
         return parser
 
     def take_action(self, parsed_args):
diff --git a/heatclient/osc/v1/event.py b/heatclient/osc/v1/event.py
index 017803a4..ea5ff16d 100644
--- a/heatclient/osc/v1/event.py
+++ b/heatclient/osc/v1/event.py
@@ -32,7 +32,7 @@ class ShowEvent(command.ShowOne):
     log = logging.getLogger(__name__ + '.ShowEvent')
 
     def get_parser(self, prog_name):
-        parser = super(ShowEvent, self).get_parser(prog_name)
+        parser = super().get_parser(prog_name)
         parser.add_argument(
             'stack',
             metavar='<stack>',
@@ -96,7 +96,7 @@ class ListEvent(command.Lister):
         return 'heatclient.event.formatter.list'
 
     def get_parser(self, prog_name):
-        parser = super(ListEvent, self).get_parser(prog_name)
+        parser = super().get_parser(prog_name)
         parser.add_argument(
             'stack',
             metavar='<stack>',
diff --git a/heatclient/osc/v1/resource.py b/heatclient/osc/v1/resource.py
index a30bae21..b2d893f0 100644
--- a/heatclient/osc/v1/resource.py
+++ b/heatclient/osc/v1/resource.py
@@ -33,7 +33,7 @@ class ResourceShow(command.ShowOne):
     log = logging.getLogger(__name__ + '.ResourceShowStack')
 
     def get_parser(self, prog_name):
-        parser = super(ResourceShow, self).get_parser(prog_name)
+        parser = super().get_parser(prog_name)
         parser.add_argument(
             'stack',
             metavar='<stack>',
@@ -80,7 +80,7 @@ class ResourceList(command.Lister):
         return 'heatclient.resource.formatter.list'
 
     def get_parser(self, prog_name):
-        parser = super(ResourceList, self).get_parser(prog_name)
+        parser = super().get_parser(prog_name)
         parser.add_argument(
             'stack',
             metavar='<stack>',
@@ -153,7 +153,7 @@ class ResourceMetadata(format_utils.JsonFormat):
     log = logging.getLogger(__name__ + ".ResourceMetadata")
 
     def get_parser(self, prog_name):
-        parser = super(ResourceMetadata, self).get_parser(prog_name)
+        parser = super().get_parser(prog_name)
         parser.add_argument(
             'stack',
             metavar='<stack>',
@@ -194,7 +194,7 @@ class ResourceSignal(command.Command):
     log = logging.getLogger(__name__ + ".ResourceSignal")
 
     def get_parser(self, prog_name):
-        parser = super(ResourceSignal, self).get_parser(prog_name)
+        parser = super().get_parser(prog_name)
         parser.add_argument(
             'stack',
             metavar='<stack>',
@@ -261,7 +261,7 @@ class ResourceMarkUnhealthy(command.Command):
     log = logging.getLogger(__name__ + ".ResourceMarkUnhealthy")
 
     def get_parser(self, prog_name):
-        parser = super(ResourceMarkUnhealthy, self).get_parser(prog_name)
+        parser = super().get_parser(prog_name)
         parser.add_argument(
             'stack',
             metavar='<stack>',
diff --git a/heatclient/osc/v1/resource_type.py b/heatclient/osc/v1/resource_type.py
index 128b6dcd..6e5cf634 100644
--- a/heatclient/osc/v1/resource_type.py
+++ b/heatclient/osc/v1/resource_type.py
@@ -30,8 +30,7 @@ class ResourceTypeShow(format_utils.YamlFormat):
     log = logging.getLogger(__name__ + ".ResourceTypeShow")
 
     def get_parser(self, prog_name):
-        parser = super(ResourceTypeShow,
-                       self).get_parser(prog_name)
+        parser = super().get_parser(prog_name)
         parser.add_argument(
             'resource_type',
             metavar='<resource-type>',
@@ -90,8 +89,7 @@ class ResourceTypeList(command.Lister):
     log = logging.getLogger(__name__ + '.ResourceTypeList')
 
     def get_parser(self, prog_name):
-        parser = super(ResourceTypeList,
-                       self).get_parser(prog_name)
+        parser = super().get_parser(prog_name)
         parser.add_argument(
             '--filter',
             dest='filter',
diff --git a/heatclient/osc/v1/service.py b/heatclient/osc/v1/service.py
index 09dec4d1..3ca042ca 100644
--- a/heatclient/osc/v1/service.py
+++ b/heatclient/osc/v1/service.py
@@ -25,7 +25,7 @@ class ListService(command.Lister):
     log = logging.getLogger(__name__ + ".ListService")
 
     def get_parser(self, prog_name):
-        parser = super(ListService, self).get_parser(prog_name)
+        parser = super().get_parser(prog_name)
         return parser
 
     def take_action(self, parsed_args):
diff --git a/heatclient/osc/v1/snapshot.py b/heatclient/osc/v1/snapshot.py
index 80882851..1ff1384a 100644
--- a/heatclient/osc/v1/snapshot.py
+++ b/heatclient/osc/v1/snapshot.py
@@ -31,7 +31,7 @@ class ListSnapshot(command.Lister):
     log = logging.getLogger(__name__ + ".ListSnapshot")
 
     def get_parser(self, prog_name):
-        parser = super(ListSnapshot, self).get_parser(prog_name)
+        parser = super().get_parser(prog_name)
         parser.add_argument(
             'stack',
             metavar='<stack>',
@@ -66,7 +66,7 @@ class ShowSnapshot(format_utils.YamlFormat):
     log = logging.getLogger(__name__ + ".ShowSnapshot")
 
     def get_parser(self, prog_name):
-        parser = super(ShowSnapshot, self).get_parser(prog_name)
+        parser = super().get_parser(prog_name)
         parser.add_argument(
             'stack',
             metavar='<stack>',
@@ -105,7 +105,7 @@ class RestoreSnapshot(command.Command):
     log = logging.getLogger(__name__ + ".RestoreSnapshot")
 
     def get_parser(self, prog_name):
-        parser = super(RestoreSnapshot, self).get_parser(prog_name)
+        parser = super().get_parser(prog_name)
         parser.add_argument(
             'stack',
             metavar='<stack>',
@@ -141,7 +141,7 @@ class CreateSnapshot(command.ShowOne):
     log = logging.getLogger(__name__ + ".CreateSnapshot")
 
     def get_parser(self, prog_name):
-        parser = super(CreateSnapshot, self).get_parser(prog_name)
+        parser = super().get_parser(prog_name)
         parser.add_argument(
             'stack',
             metavar='<stack>',
@@ -181,7 +181,7 @@ class DeleteSnapshot(command.Command):
     log = logging.getLogger(__name__ + ".DeleteSnapshot")
 
     def get_parser(self, prog_name):
-        parser = super(DeleteSnapshot, self).get_parser(prog_name)
+        parser = super().get_parser(prog_name)
         parser.add_argument(
             'stack',
             metavar='<stack>',
diff --git a/heatclient/osc/v1/software_config.py b/heatclient/osc/v1/software_config.py
index dcfa5d66..89378310 100644
--- a/heatclient/osc/v1/software_config.py
+++ b/heatclient/osc/v1/software_config.py
@@ -34,7 +34,7 @@ class DeleteConfig(command.Command):
     log = logging.getLogger(__name__ + ".DeleteConfig")
 
     def get_parser(self, prog_name):
-        parser = super(DeleteConfig, self).get_parser(prog_name)
+        parser = super().get_parser(prog_name)
         parser.add_argument(
             'config',
             metavar='<config>',
@@ -76,7 +76,7 @@ class ListConfig(command.Lister):
     log = logging.getLogger(__name__ + ".ListConfig")
 
     def get_parser(self, prog_name):
-        parser = super(ListConfig, self).get_parser(prog_name)
+        parser = super().get_parser(prog_name)
         parser.add_argument(
             '--limit',
             metavar='<limit>',
@@ -114,7 +114,7 @@ class CreateConfig(format_utils.JsonFormat):
     log = logging.getLogger(__name__ + ".CreateConfig")
 
     def get_parser(self, prog_name):
-        parser = super(CreateConfig, self).get_parser(prog_name)
+        parser = super().get_parser(prog_name)
         parser.add_argument(
             'name',
             metavar='<config-name>',
@@ -192,7 +192,7 @@ class ShowConfig(format_utils.YamlFormat):
     log = logging.getLogger(__name__ + ".ShowConfig")
 
     def get_parser(self, prog_name):
-        parser = super(ShowConfig, self).get_parser(prog_name)
+        parser = super().get_parser(prog_name)
         parser.add_argument(
             'config',
             metavar='<config>',
diff --git a/heatclient/osc/v1/software_deployment.py b/heatclient/osc/v1/software_deployment.py
index 825d8fb7..6c5cfd92 100644
--- a/heatclient/osc/v1/software_deployment.py
+++ b/heatclient/osc/v1/software_deployment.py
@@ -33,7 +33,7 @@ class CreateDeployment(format_utils.YamlFormat):
     log = logging.getLogger(__name__ + '.CreateDeployment')
 
     def get_parser(self, prog_name):
-        parser = super(CreateDeployment, self).get_parser(prog_name)
+        parser = super().get_parser(prog_name)
         parser.add_argument(
             'name',
             metavar='<deployment-name>',
@@ -136,7 +136,7 @@ class DeleteDeployment(command.Command):
     log = logging.getLogger(__name__ + '.DeleteDeployment')
 
     def get_parser(self, prog_name):
-        parser = super(DeleteDeployment, self).get_parser(prog_name)
+        parser = super().get_parser(prog_name)
         parser.add_argument(
             'deployment',
             metavar='<deployment>',
@@ -185,7 +185,7 @@ class ListDeployment(command.Lister):
     log = logging.getLogger(__name__ + '.ListDeployment')
 
     def get_parser(self, prog_name):
-        parser = super(ListDeployment, self).get_parser(prog_name)
+        parser = super().get_parser(prog_name)
         parser.add_argument(
             '--server',
             metavar='<server>',
@@ -225,7 +225,7 @@ class ShowDeployment(command.ShowOne):
     log = logging.getLogger(__name__ + ".ShowSoftwareDeployment")
 
     def get_parser(self, prog_name):
-        parser = super(ShowDeployment, self).get_parser(prog_name)
+        parser = super().get_parser(prog_name)
         parser.add_argument(
             'deployment',
             metavar='<deployment>',
@@ -272,7 +272,7 @@ class ShowMetadataDeployment(command.Command):
     log = logging.getLogger(__name__ + '.ShowMetadataDeployment')
 
     def get_parser(self, prog_name):
-        parser = super(ShowMetadataDeployment, self).get_parser(prog_name)
+        parser = super().get_parser(prog_name)
         parser.add_argument(
             'server',
             metavar='<server>',
@@ -294,7 +294,7 @@ class ShowOutputDeployment(command.Command):
     log = logging.getLogger(__name__ + '.ShowOutputDeployment')
 
     def get_parser(self, prog_name):
-        parser = super(ShowOutputDeployment, self).get_parser(prog_name)
+        parser = super().get_parser(prog_name)
         parser.add_argument(
             'deployment',
             metavar='<deployment>',
diff --git a/heatclient/osc/v1/stack.py b/heatclient/osc/v1/stack.py
index e1b14a83..1d3ec7c7 100644
--- a/heatclient/osc/v1/stack.py
+++ b/heatclient/osc/v1/stack.py
@@ -41,7 +41,7 @@ class CreateStack(command.ShowOne):
     log = logging.getLogger(__name__ + '.CreateStack')
 
     def get_parser(self, prog_name):
-        parser = super(CreateStack, self).get_parser(prog_name)
+        parser = super().get_parser(prog_name)
         parser.add_argument(
             '-e', '--environment',
             metavar='<environment>',
@@ -219,7 +219,7 @@ class UpdateStack(command.ShowOne):
     log = logging.getLogger(__name__ + '.UpdateStack')
 
     def get_parser(self, prog_name):
-        parser = super(UpdateStack, self).get_parser(prog_name)
+        parser = super().get_parser(prog_name)
         parser.add_argument(
             '-t', '--template', metavar='<template>',
             help=_('Path to the template')
@@ -423,7 +423,7 @@ class ShowStack(command.ShowOne):
     log = logging.getLogger(__name__ + ".ShowStack")
 
     def get_parser(self, prog_name):
-        parser = super(ShowStack, self).get_parser(prog_name)
+        parser = super().get_parser(prog_name)
         parser.add_argument(
             'stack',
             metavar='<stack>',
@@ -499,7 +499,7 @@ class ListStack(command.Lister):
     log = logging.getLogger(__name__ + '.ListStack')
 
     def get_parser(self, prog_name):
-        parser = super(ListStack, self).get_parser(prog_name)
+        parser = super().get_parser(prog_name)
         parser.add_argument(
             '--deleted',
             action='store_true',
@@ -601,7 +601,7 @@ class EnvironmentShowStack(format_utils.YamlFormat):
     log = logging.getLogger(__name__)
 
     def get_parser(self, prog_name):
-        parser = super(EnvironmentShowStack, self).get_parser(prog_name)
+        parser = super().get_parser(prog_name)
         parser.add_argument(
             'stack',
             metavar='<NAME or ID>',
@@ -634,7 +634,7 @@ class ListFileStack(format_utils.YamlFormat):
     log = logging.getLogger(__name__)
 
     def get_parser(self, prog_name):
-        parser = super(ListFileStack, self).get_parser(prog_name)
+        parser = super().get_parser(prog_name)
         parser.add_argument(
             'stack',
             metavar='<NAME or ID>',
@@ -728,7 +728,7 @@ class DeleteStack(command.Command):
     log = logging.getLogger(__name__ + ".DeleteStack")
 
     def get_parser(self, prog_name):
-        parser = super(DeleteStack, self).get_parser(prog_name)
+        parser = super().get_parser(prog_name)
         parser.add_argument(
             'stack',
             metavar='<stack>',
@@ -822,7 +822,7 @@ class AdoptStack(command.ShowOne):
     log = logging.getLogger(__name__ + '.AdoptStack')
 
     def get_parser(self, prog_name):
-        parser = super(AdoptStack, self).get_parser(prog_name)
+        parser = super().get_parser(prog_name)
         parser.add_argument(
             'name',
             metavar='<stack-name>',
@@ -907,7 +907,7 @@ class AbandonStack(format_utils.JsonFormat):
     log = logging.getLogger(__name__ + '.AbandonStack')
 
     def get_parser(self, prog_name):
-        parser = super(AbandonStack, self).get_parser(prog_name)
+        parser = super().get_parser(prog_name)
         parser.add_argument(
             'stack',
             metavar='<stack>',
@@ -937,7 +937,7 @@ class AbandonStack(format_utils.JsonFormat):
                 with open(parsed_args.output_file, 'w') as f:
                     f.write(jsonutils.dumps(stack, indent=2))
                     return [], None
-            except IOError as e:
+            except OSError as e:
                 raise exc.CommandError(str(e))
 
         data = list(stack.values())
@@ -951,7 +951,7 @@ class ExportStack(format_utils.JsonFormat):
     log = logging.getLogger(__name__ + '.ExportStack')
 
     def get_parser(self, prog_name):
-        parser = super(ExportStack, self).get_parser(prog_name)
+        parser = super().get_parser(prog_name)
         parser.add_argument(
             'stack',
             metavar='<stack>',
@@ -981,7 +981,7 @@ class ExportStack(format_utils.JsonFormat):
                 with open(parsed_args.output_file, 'w') as f:
                     f.write(jsonutils.dumps(data_info, indent=2))
                     return [], None
-            except IOError as e:
+            except OSError as e:
                 raise exc.CommandError(str(e))
 
         data = list(data_info.values())
@@ -995,7 +995,7 @@ class OutputShowStack(command.ShowOne):
     log = logging.getLogger(__name__ + '.OutputShowStack')
 
     def get_parser(self, prog_name):
-        parser = super(OutputShowStack, self).get_parser(prog_name)
+        parser = super().get_parser(prog_name)
         parser.add_argument(
             'stack',
             metavar='<stack>',
@@ -1075,7 +1075,7 @@ class OutputListStack(command.Lister):
     log = logging.getLogger(__name__ + '.OutputListStack')
 
     def get_parser(self, prog_name):
-        parser = super(OutputListStack, self).get_parser(prog_name)
+        parser = super().get_parser(prog_name)
         parser.add_argument(
             'stack',
             metavar='<stack>',
@@ -1112,7 +1112,7 @@ class TemplateShowStack(format_utils.YamlFormat):
     log = logging.getLogger(__name__ + '.TemplateShowStack')
 
     def get_parser(self, prog_name):
-        parser = super(TemplateShowStack, self).get_parser(prog_name)
+        parser = super().get_parser(prog_name)
         parser.add_argument(
             'stack',
             metavar='<stack>',
@@ -1140,7 +1140,7 @@ class StackActionBase(command.Lister):
     log = logging.getLogger(__name__ + '.StackActionBase')
 
     def _get_parser(self, prog_name, stack_help, wait_help):
-        parser = super(StackActionBase, self).get_parser(prog_name)
+        parser = super().get_parser(prog_name)
         parser.add_argument(
             'stack',
             metavar='<stack>',
@@ -1341,7 +1341,7 @@ class StackHookPoll(command.Lister):
     log = logging.getLogger(__name__ + '.StackHookPoll')
 
     def get_parser(self, prog_name):
-        parser = super(StackHookPoll, self).get_parser(prog_name)
+        parser = super().get_parser(prog_name)
         parser.add_argument(
             'stack',
             metavar='<stack>',
@@ -1410,7 +1410,7 @@ class StackHookClear(command.Command):
     log = logging.getLogger(__name__ + '.StackHookClear')
 
     def get_parser(self, prog_name):
-        parser = super(StackHookClear, self).get_parser(prog_name)
+        parser = super().get_parser(prog_name)
         parser.add_argument(
             'stack',
             metavar='<stack>',
diff --git a/heatclient/osc/v1/stack_failures.py b/heatclient/osc/v1/stack_failures.py
index 8426499b..81e8c83e 100644
--- a/heatclient/osc/v1/stack_failures.py
+++ b/heatclient/osc/v1/stack_failures.py
@@ -32,7 +32,7 @@ class ListStackFailures(command.Command):
                              long=parsed_args.long)
 
     def get_parser(self, prog_name):
-        parser = super(ListStackFailures, self).get_parser(prog_name)
+        parser = super().get_parser(prog_name)
         parser.add_argument(
             'stack',
             metavar='<stack>',
diff --git a/heatclient/osc/v1/template.py b/heatclient/osc/v1/template.py
index 41419a1a..5f5d7691 100644
--- a/heatclient/osc/v1/template.py
+++ b/heatclient/osc/v1/template.py
@@ -64,7 +64,7 @@ class FunctionList(command.Lister):
     log = logging.getLogger(__name__ + '.FunctionList')
 
     def get_parser(self, prog_name):
-        parser = super(FunctionList, self).get_parser(prog_name)
+        parser = super().get_parser(prog_name)
         parser.add_argument(
             'template_version',
             metavar='<template-version>',
@@ -105,7 +105,7 @@ class Validate(format_utils.YamlFormat):
     log = logging.getLogger(__name__ + ".Validate")
 
     def get_parser(self, prog_name):
-        parser = super(Validate, self).get_parser(prog_name)
+        parser = super().get_parser(prog_name)
         parser.add_argument(
             '-e', '--environment',
             metavar='<environment>',
diff --git a/heatclient/shell.py b/heatclient/shell.py
index 9123bacc..a0fb194b 100644
--- a/heatclient/shell.py
+++ b/heatclient/shell.py
@@ -32,7 +32,7 @@ from heatclient import exc
 osprofiler_profiler = importutils.try_import("osprofiler.profiler")
 
 
-class HeatShell(object):
+class HeatShell:
 
     def _append_global_identity_args(self, parser):
         # FIXME(gyee): these are global identity (Keystone) arguments which
@@ -592,8 +592,8 @@ class HeatShell(object):
 class HelpFormatter(argparse.HelpFormatter):
     def start_section(self, heading):
         # Title-case the headings
-        heading = '%s%s' % (heading[0].upper(), heading[1:])
-        super(HelpFormatter, self).start_section(heading)
+        heading = '{}{}'.format(heading[0].upper(), heading[1:])
+        super().start_section(heading)
 
 
 def main(args=None):
diff --git a/heatclient/tests/functional/osc/v1/base.py b/heatclient/tests/functional/osc/v1/base.py
index 1befa0ef..8e9fa4bd 100644
--- a/heatclient/tests/functional/osc/v1/base.py
+++ b/heatclient/tests/functional/osc/v1/base.py
@@ -21,7 +21,7 @@ class OpenStackClientTestBase(base.ClientTestBase):
     """Command line client base functions."""
 
     def setUp(self):
-        super(OpenStackClientTestBase, self).setUp()
+        super().setUp()
         self.parser = output_parser
 
     def _get_clients(self):
@@ -48,7 +48,7 @@ class OpenStackClientTestBase(base.ClientTestBase):
         items = self.parser.listing(output)
         for item in items:
             obj[item['Field']] = str(item['Value'])
-        return dict((self._key_name(k), v) for k, v in obj.items())
+        return {self._key_name(k): v for k, v in obj.items()}
 
     def _key_name(self, key):
         return key.lower().replace(' ', '_')
@@ -60,7 +60,7 @@ class OpenStackClientTestBase(base.ClientTestBase):
             if item['ID'] == id:
                 obj = item
                 break
-        return dict((self._key_name(k), v) for k, v in obj.items())
+        return {self._key_name(k): v for k, v in obj.items()}
 
     def _stack_create(self, name, template, parameters=[], wait=True):
         cmd = 'stack create ' + name
diff --git a/heatclient/tests/functional/osc/v1/test_stack.py b/heatclient/tests/functional/osc/v1/test_stack.py
index d5bc6535..17705d34 100644
--- a/heatclient/tests/functional/osc/v1/test_stack.py
+++ b/heatclient/tests/functional/osc/v1/test_stack.py
@@ -23,7 +23,7 @@ class OpenStackClientStackTest(base.OpenStackClientTestBase):
     """
 
     def setUp(self):
-        super(OpenStackClientStackTest, self).setUp()
+        super().setUp()
         self.stack_name = utils.rand_name(name='test-stack')
 
     def _stack_create_minimal(self, from_url=False):
diff --git a/heatclient/tests/unit/fakes.py b/heatclient/tests/unit/fakes.py
index 1252a1e3..5f391c3f 100644
--- a/heatclient/tests/unit/fakes.py
+++ b/heatclient/tests/unit/fakes.py
@@ -14,11 +14,11 @@
 from oslo_serialization import jsonutils
 
 
-class FakeRaw(object):
+class FakeRaw:
     version = 110
 
 
-class FakeHTTPResponse(object):
+class FakeHTTPResponse:
 
     version = 1.1
 
diff --git a/heatclient/tests/unit/osc/fakes.py b/heatclient/tests/unit/osc/fakes.py
index e45cab17..d81f89d4 100644
--- a/heatclient/tests/unit/osc/fakes.py
+++ b/heatclient/tests/unit/osc/fakes.py
@@ -18,7 +18,7 @@ import json
 import requests
 
 
-class FakeStdout(object):
+class FakeStdout:
     def __init__(self):
         self.content = []
 
@@ -34,7 +34,7 @@ class FakeStdout(object):
 
 class FakeResponse(requests.Response):
     def __init__(self, headers={}, status_code=200, data=None, encoding=None):
-        super(FakeResponse, self).__init__()
+        super().__init__()
 
         self.status_code = status_code
 
diff --git a/heatclient/tests/unit/osc/utils.py b/heatclient/tests/unit/osc/utils.py
index dc487905..53963661 100644
--- a/heatclient/tests/unit/osc/utils.py
+++ b/heatclient/tests/unit/osc/utils.py
@@ -51,7 +51,7 @@ class TestCommand(TestCase):
     """Test cliff command classes"""
 
     def setUp(self):
-        super(TestCommand, self).setUp()
+        super().setUp()
         # Build up a fake app
         self.fake_stdout = fakes.FakeStdout()
         self.app = mock.MagicMock()
diff --git a/heatclient/tests/unit/osc/v1/fakes.py b/heatclient/tests/unit/osc/v1/fakes.py
index dec0c6aa..41f5c400 100644
--- a/heatclient/tests/unit/osc/v1/fakes.py
+++ b/heatclient/tests/unit/osc/v1/fakes.py
@@ -20,6 +20,6 @@ from heatclient.tests.unit.osc import utils
 
 class TestOrchestrationv1(utils.TestCommand):
     def setUp(self):
-        super(TestOrchestrationv1, self).setUp()
+        super().setUp()
 
         self.app.client_manager.orchestration = mock.MagicMock()
diff --git a/heatclient/tests/unit/osc/v1/test_build_info.py b/heatclient/tests/unit/osc/v1/test_build_info.py
index a43fd8a1..08237456 100644
--- a/heatclient/tests/unit/osc/v1/test_build_info.py
+++ b/heatclient/tests/unit/osc/v1/test_build_info.py
@@ -28,7 +28,7 @@ class TestBuildInfo(orchestration_fakes.TestOrchestrationv1):
     }
 
     def setUp(self):
-        super(TestBuildInfo, self).setUp()
+        super().setUp()
         self.cmd = osc_build_info.BuildInfo(self.app, None)
         self.mock_client = self.app.client_manager.orchestration
         self.mock_client.build_info.build_info = mock.Mock(
diff --git a/heatclient/tests/unit/osc/v1/test_event.py b/heatclient/tests/unit/osc/v1/test_event.py
index 5edaf202..6f8a9151 100644
--- a/heatclient/tests/unit/osc/v1/test_event.py
+++ b/heatclient/tests/unit/osc/v1/test_event.py
@@ -27,7 +27,7 @@ load_tests = testscenarios.load_tests_apply_scenarios
 
 class TestEvent(fakes.TestOrchestrationv1):
     def setUp(self):
-        super(TestEvent, self).setUp()
+        super().setUp()
         self.mock_client = self.app.client_manager.orchestration
         self.event_client = self.app.client_manager.orchestration.events
         self.stack_client = self.app.client_manager.orchestration.stacks
@@ -56,7 +56,7 @@ class TestEventShow(TestEvent):
     }
 
     def setUp(self):
-        super(TestEventShow, self).setUp()
+        super().setUp()
         self.cmd = event.ShowEvent(self.app, None)
 
     def test_event_show(self):
@@ -108,7 +108,7 @@ class TestEventList(TestEvent):
               'resource_status_reason', 'event_time', 'physical_resource_id',
               'logical_resource_id']
 
-    class MockEvent(object):
+    class MockEvent:
 
         data = {
             'event_time': '2015-11-13T10:02:17',
@@ -129,7 +129,7 @@ class TestEventList(TestEvent):
                 raise AttributeError
 
     def setUp(self):
-        super(TestEventList, self).setUp()
+        super().setUp()
         self.cmd = event.ListEvent(self.app, None)
         self.event = self.MockEvent()
         self.event_client.list.return_value = [self.event]
diff --git a/heatclient/tests/unit/osc/v1/test_resource.py b/heatclient/tests/unit/osc/v1/test_resource.py
index c9e4a603..8c8e48a9 100644
--- a/heatclient/tests/unit/osc/v1/test_resource.py
+++ b/heatclient/tests/unit/osc/v1/test_resource.py
@@ -24,7 +24,7 @@ from heatclient.v1 import resources as v1_resources
 
 class TestResource(orchestration_fakes.TestOrchestrationv1):
     def setUp(self):
-        super(TestResource, self).setUp()
+        super().setUp()
         self.resource_client = self.app.client_manager.orchestration.resources
 
 
@@ -49,7 +49,7 @@ class TestStackResourceShow(TestResource):
     }
 
     def setUp(self):
-        super(TestStackResourceShow, self).setUp()
+        super().setUp()
         self.cmd = resource.ResourceShow(self.app, None)
         self.resource_client.get.return_value = v1_resources.Resource(
             None, self.response)
@@ -117,7 +117,7 @@ class TestStackResourceList(TestResource):
             'CREATE_COMPLETE', '2016-02-01T20:20:53']
 
     def setUp(self):
-        super(TestStackResourceList, self).setUp()
+        super().setUp()
         self.cmd = resource.ResourceList(self.app, None)
         self.resource_client.list.return_value = [
             v1_resources.Resource(None, self.response)]
@@ -218,7 +218,7 @@ class TestStackResourceList(TestResource):
 class TestResourceMetadata(TestResource):
 
     def setUp(self):
-        super(TestResourceMetadata, self).setUp()
+        super().setUp()
         self.cmd = resource.ResourceMetadata(self.app, None)
         self.resource_client.metadata.return_value = {}
 
@@ -254,7 +254,7 @@ class TestResourceMetadata(TestResource):
 class TestResourceSignal(TestResource):
 
     def setUp(self):
-        super(TestResourceSignal, self).setUp()
+        super().setUp()
         self.cmd = resource.ResourceSignal(self.app, None)
 
     def test_resource_signal(self):
@@ -323,7 +323,7 @@ class TestResourceSignal(TestResource):
 
 class TestResourceMarkUnhealthy(TestResource):
     def setUp(self):
-        super(TestResourceMarkUnhealthy, self).setUp()
+        super().setUp()
         self.cmd = resource.ResourceMarkUnhealthy(self.app, None)
         self.resource_client.mark_unhealthy = mock.Mock()
 
diff --git a/heatclient/tests/unit/osc/v1/test_resource_type.py b/heatclient/tests/unit/osc/v1/test_resource_type.py
index b972cb95..0afd8b42 100644
--- a/heatclient/tests/unit/osc/v1/test_resource_type.py
+++ b/heatclient/tests/unit/osc/v1/test_resource_type.py
@@ -21,14 +21,14 @@ from heatclient.v1 import resource_types
 
 class TestResourceType(orchestration_fakes.TestOrchestrationv1):
     def setUp(self):
-        super(TestResourceType, self).setUp()
+        super().setUp()
         self.mock_client = self.app.client_manager.orchestration
 
 
 class TestResourceTypeShow(TestResourceType):
 
     def setUp(self):
-        super(TestResourceTypeShow, self).setUp()
+        super().setUp()
         self.cmd = resource_type.ResourceTypeShow(self.app, None)
         self.mock_client.resource_types.get.return_value = {}
         self.mock_client.resource_types.generate_template.return_value = {}
@@ -130,7 +130,7 @@ class TestTypeList(TestResourceType):
     ]
 
     def setUp(self):
-        super(TestTypeList, self).setUp()
+        super().setUp()
         self.cmd = resource_type.ResourceTypeList(self.app, None)
         self.mock_client.resource_types.list.return_value = self.list_response
 
diff --git a/heatclient/tests/unit/osc/v1/test_service.py b/heatclient/tests/unit/osc/v1/test_service.py
index 5f8573e8..82adeb4a 100644
--- a/heatclient/tests/unit/osc/v1/test_service.py
+++ b/heatclient/tests/unit/osc/v1/test_service.py
@@ -49,7 +49,7 @@ class TestServiceList(orchestration_fakes.TestOrchestrationv1):
                'Topic', 'Updated At', 'Status']
 
     def setUp(self):
-        super(TestServiceList, self).setUp()
+        super().setUp()
         self.cmd = osc_service.ListService(self.app, None)
         self.mock_client = self.app.client_manager.orchestration
         self.mock_client.services.list.return_value = self.response
diff --git a/heatclient/tests/unit/osc/v1/test_snapshot.py b/heatclient/tests/unit/osc/v1/test_snapshot.py
index 6b583030..d22dee89 100644
--- a/heatclient/tests/unit/osc/v1/test_snapshot.py
+++ b/heatclient/tests/unit/osc/v1/test_snapshot.py
@@ -22,14 +22,14 @@ from heatclient.tests.unit.osc.v1 import fakes as orchestration_fakes
 
 class TestStack(orchestration_fakes.TestOrchestrationv1):
     def setUp(self):
-        super(TestStack, self).setUp()
+        super().setUp()
         self.mock_client = self.app.client_manager.orchestration
         self.stack_client = self.app.client_manager.orchestration.stacks
 
 
 class TestListSnapshot(TestStack):
     def setUp(self):
-        super(TestListSnapshot, self).setUp()
+        super().setUp()
         self.cmd = snapshot.ListSnapshot(self.app, None)
         self.stack_client.snapshot_list.return_value = {'snapshots': []}
 
@@ -54,7 +54,7 @@ class TestListSnapshot(TestStack):
 
 class TestSnapshotShow(TestStack):
     def setUp(self):
-        super(TestSnapshotShow, self).setUp()
+        super().setUp()
         self.cmd = snapshot.ShowSnapshot(self.app, None)
 
     def test_snapshot_show(self):
@@ -77,7 +77,7 @@ class TestSnapshotShow(TestStack):
 
 class TestRestoreSnapshot(TestStack):
     def setUp(self):
-        super(TestRestoreSnapshot, self).setUp()
+        super().setUp()
         self.cmd = snapshot.RestoreSnapshot(self.app, None)
 
     def test_snapshot_restore(self):
@@ -110,7 +110,7 @@ class TestSnapshotCreate(TestStack):
     }
 
     def setUp(self):
-        super(TestSnapshotCreate, self).setUp()
+        super().setUp()
         self.cmd = snapshot.CreateSnapshot(self.app, None)
 
     def test_snapshot_create(self):
@@ -141,7 +141,7 @@ class TestSnapshotCreate(TestStack):
 
 class TestSnapshotDelete(TestStack):
     def setUp(self):
-        super(TestSnapshotDelete, self).setUp()
+        super().setUp()
         self.cmd = snapshot.DeleteSnapshot(self.app, None)
 
     def test_snapshot_delete(self):
diff --git a/heatclient/tests/unit/osc/v1/test_software_config.py b/heatclient/tests/unit/osc/v1/test_software_config.py
index 3d544bdb..4b96af3d 100644
--- a/heatclient/tests/unit/osc/v1/test_software_config.py
+++ b/heatclient/tests/unit/osc/v1/test_software_config.py
@@ -24,14 +24,14 @@ from heatclient.v1 import software_configs
 
 class TestConfig(orchestration_fakes.TestOrchestrationv1):
     def setUp(self):
-        super(TestConfig, self).setUp()
+        super().setUp()
         self.mock_client = self.app.client_manager.orchestration
 
 
 class TestDeleteConfig(TestConfig):
 
     def setUp(self):
-        super(TestDeleteConfig, self).setUp()
+        super().setUp()
         self.cmd = software_config.DeleteConfig(self.app, None)
         self.mock_delete = self.mock_client.software_configs.delete
 
@@ -68,7 +68,7 @@ class TestDeleteConfig(TestConfig):
 class TestListConfig(TestConfig):
 
     def setUp(self):
-        super(TestListConfig, self).setUp()
+        super().setUp()
         self.cmd = software_config.ListConfig(self.app, None)
         self.mock_client.software_configs.list.return_value = [
             software_configs.SoftwareConfig(None, {})]
@@ -96,7 +96,7 @@ class TestListConfig(TestConfig):
 class TestCreateConfig(TestConfig):
 
     def setUp(self):
-        super(TestCreateConfig, self).setUp()
+        super().setUp()
         self.cmd = software_config.CreateConfig(self.app, None)
         self.mock_client.software_configs.create.return_value = \
             software_configs.SoftwareConfig(None, {})
@@ -235,7 +235,7 @@ class TestConfigShow(TestConfig):
     response = dict(zip(columns, data))
 
     def setUp(self):
-        super(TestConfigShow, self).setUp()
+        super().setUp()
         self.cmd = software_config.ShowConfig(self.app, None)
         self.mock_client.software_configs.get.return_value = \
             software_configs.SoftwareConfig(None, self.response)
diff --git a/heatclient/tests/unit/osc/v1/test_software_deployment.py b/heatclient/tests/unit/osc/v1/test_software_deployment.py
index 9edb6a9c..67cb9ae4 100644
--- a/heatclient/tests/unit/osc/v1/test_software_deployment.py
+++ b/heatclient/tests/unit/osc/v1/test_software_deployment.py
@@ -25,7 +25,7 @@ from heatclient.v1 import software_deployments
 
 class TestDeployment(orchestration_fakes.TestOrchestrationv1):
     def setUp(self):
-        super(TestDeployment, self).setUp()
+        super().setUp()
         self.mock_client = self.app.client_manager.orchestration
         self.config_client = self.mock_client.software_configs
         self.sd_client = self.mock_client.software_deployments
@@ -108,7 +108,7 @@ class TestDeploymentCreate(TestDeployment):
     }
 
     def setUp(self):
-        super(TestDeploymentCreate, self).setUp()
+        super().setUp()
         self.cmd = software_deployment.CreateDeployment(self.app, None)
         self.config_client.create.return_value = \
             software_configs.SoftwareConfig(None, self.config)
@@ -220,7 +220,7 @@ class TestDeploymentCreate(TestDeployment):
 class TestDeploymentDelete(TestDeployment):
 
     def setUp(self):
-        super(TestDeploymentDelete, self).setUp()
+        super().setUp()
         self.cmd = software_deployment.DeleteDeployment(self.app, None)
 
     def test_deployment_delete_success(self):
@@ -284,7 +284,7 @@ class TestDeploymentList(TestDeployment):
     }
 
     def setUp(self):
-        super(TestDeploymentList, self).setUp()
+        super().setUp()
         self.cmd = software_deployment.ListDeployment(self.app, None)
         self.sd_client.list = mock.MagicMock(return_value=[self.data])
 
@@ -332,7 +332,7 @@ class TestDeploymentShow(TestDeployment):
     }}
 
     def setUp(self):
-        super(TestDeploymentShow, self).setUp()
+        super().setUp()
         self.cmd = software_deployment.ShowDeployment(self.app, None)
 
     def test_deployment_show(self):
@@ -378,7 +378,7 @@ class TestDeploymentShow(TestDeployment):
 class TestDeploymentMetadataShow(TestDeployment):
 
     def setUp(self):
-        super(TestDeploymentMetadataShow, self).setUp()
+        super().setUp()
         self.cmd = software_deployment.ShowMetadataDeployment(self.app, None)
         self.sd_client.metadata.return_value = {}
 
@@ -406,7 +406,7 @@ class TestDeploymentOutputShow(TestDeployment):
     }
 
     def setUp(self):
-        super(TestDeploymentOutputShow, self).setUp()
+        super().setUp()
         self.cmd = software_deployment.ShowOutputDeployment(self.app, None)
 
     def test_deployment_output_show(self):
diff --git a/heatclient/tests/unit/osc/v1/test_stack.py b/heatclient/tests/unit/osc/v1/test_stack.py
index 3caa5bd1..fd641964 100644
--- a/heatclient/tests/unit/osc/v1/test_stack.py
+++ b/heatclient/tests/unit/osc/v1/test_stack.py
@@ -34,7 +34,7 @@ load_tests = testscenarios.load_tests_apply_scenarios
 
 class TestStack(orchestration_fakes.TestOrchestrationv1):
     def setUp(self):
-        super(TestStack, self).setUp()
+        super().setUp()
         self.mock_client = self.app.client_manager.orchestration
         self.stack_client = self.app.client_manager.orchestration.stacks
         self.projects_mock = self.app.client_manager.identity.projects
@@ -56,7 +56,7 @@ class TestStackCreate(TestStack):
     }
 
     def setUp(self):
-        super(TestStackCreate, self).setUp()
+        super().setUp()
         self.cmd = stack.CreateStack(self.app, None)
         self.stack_client.create.return_value = {'stack': {'id': '1234'}}
         self.stack_client.get.return_value = {
@@ -205,7 +205,7 @@ class TestStackUpdate(TestStack):
     }
 
     def setUp(self):
-        super(TestStackUpdate, self).setUp()
+        super().setUp()
         self.cmd = stack.UpdateStack(self.app, None)
         self.stack_client.update.return_value = {'stack': {'id': '1234'}}
         self.stack_client.preview_update.return_value = {
@@ -445,7 +445,7 @@ class TestStackShow(TestStack):
     }
 
     def setUp(self):
-        super(TestStackShow, self).setUp()
+        super().setUp()
         self.cmd = stack.ShowStack(self.app, None)
         self.stack_client.get.return_value = stacks.Stack(
             None, self.get_response)
@@ -509,7 +509,7 @@ class TestStackList(TestStack):
     data_with_project['project'] = 'test_project'
 
     def setUp(self):
-        super(TestStackList, self).setUp()
+        super().setUp()
         self.cmd = stack.ListStack(self.app, None)
         self.stack_client.list.return_value = [stacks.Stack(None, self.data)]
         utils.get_dict_properties = mock.MagicMock(return_value='')
@@ -664,7 +664,7 @@ class TestStackList(TestStack):
 class TestStackDelete(TestStack):
 
     def setUp(self):
-        super(TestStackDelete, self).setUp()
+        super().setUp()
         self.cmd = stack.DeleteStack(self.app, None)
         self.stack_client.get.side_effect = heat_exc.HTTPNotFound
 
@@ -764,9 +764,9 @@ class TestStackAdopt(TestStack):
     adopt_file = 'heatclient/tests/test_templates/adopt.json'
     adopt_with_files = ('heatclient/tests/test_templates/adopt_with_file.json')
 
-    with open(adopt_file, 'r') as f:
+    with open(adopt_file) as f:
         adopt_data = f.read()
-    with open(adopt_with_files, 'r') as f:
+    with open(adopt_with_files) as f:
         adopt_with_files_data = f.read()
 
     defaults = {
@@ -792,7 +792,7 @@ class TestStackAdopt(TestStack):
     }
 
     def setUp(self):
-        super(TestStackAdopt, self).setUp()
+        super().setUp()
         self.cmd = stack.AdoptStack(self.app, None)
         self.stack_client.create.return_value = {'stack': {'id': '1234'}}
 
@@ -866,7 +866,7 @@ class TestStackExport(TestStack):
     response = dict(zip(columns, data))
 
     def setUp(self):
-        super(TestStackExport, self).setUp()
+        super().setUp()
         self.cmd = stack.ExportStack(self.app, None)
         self.stack_client.export.return_value = self.response
 
@@ -902,7 +902,7 @@ class TestStackAbandon(TestStack):
     response = dict(zip(columns, data))
 
     def setUp(self):
-        super(TestStackAbandon, self).setUp()
+        super().setUp()
         self.cmd = stack.AbandonStack(self.app, None)
         self.stack_client.abandon.return_value = self.response
 
@@ -959,7 +959,7 @@ class TestStackOutputShow(TestStack):
     }
 
     def setUp(self):
-        super(TestStackOutputShow, self).setUp()
+        super().setUp()
         self.cmd = stack.OutputShowStack(self.app, None)
         self.stack_client.get.return_value = stacks.Stack(None, self.response)
 
@@ -1056,7 +1056,7 @@ class TestStackOutputList(TestStack):
     }
 
     def setUp(self):
-        super(TestStackOutputList, self).setUp()
+        super().setUp()
         self.cmd = stack.OutputListStack(self.app, None)
         self.stack_client.get = mock.MagicMock(
             return_value=stacks.Stack(None, self.response))
@@ -1098,7 +1098,7 @@ class TestStackTemplateShow(TestStack):
               'parameters', 'resources', 'outputs']
 
     def setUp(self):
-        super(TestStackTemplateShow, self).setUp()
+        super().setUp()
         self.cmd = stack.TemplateShowStack(self.app, None)
 
     def test_stack_template_show_full_template(self):
@@ -1133,7 +1133,7 @@ class TestStackTemplateShow(TestStack):
         self.assertRaises(exc.CommandError, self.cmd.take_action, parsed_args)
 
 
-class _TestStackCheckBase(object):
+class _TestStackCheckBase:
 
     stack = stacks.Stack(None, {
         "id": '1234',
@@ -1219,7 +1219,7 @@ class _TestStackCheckBase(object):
 class TestStackSuspend(_TestStackCheckBase, TestStack):
 
     def setUp(self):
-        super(TestStackSuspend, self).setUp()
+        super().setUp()
         self._setUp(
             stack.SuspendStack(self.app, None),
             self.mock_client.actions.suspend,
@@ -1245,7 +1245,7 @@ class TestStackSuspend(_TestStackCheckBase, TestStack):
 class TestStackResume(_TestStackCheckBase, TestStack):
 
     def setUp(self):
-        super(TestStackResume, self).setUp()
+        super().setUp()
         self._setUp(
             stack.ResumeStack(self.app, None),
             self.mock_client.actions.resume,
@@ -1279,7 +1279,7 @@ class TestStackCancel(_TestStackCheckBase, TestStack):
     })
 
     def setUp(self):
-        super(TestStackCancel, self).setUp()
+        super().setUp()
         self._setUp(
             stack.CancelStack(self.app, None),
             self.mock_client.actions.cancel_update,
@@ -1343,7 +1343,7 @@ class TestStackCancel(_TestStackCheckBase, TestStack):
 class TestStackCheck(_TestStackCheckBase, TestStack):
 
     def setUp(self):
-        super(TestStackCheck, self).setUp()
+        super().setUp()
         self._setUp(
             stack.CheckStack(self.app, None),
             self.mock_client.actions.check,
@@ -1418,7 +1418,7 @@ class TestStackHookPoll(TestStack):
             )
 
     def setUp(self):
-        super(TestStackHookPoll, self).setUp()
+        super().setUp()
         self.cmd = stack.StackHookPoll(self.app, None)
         self.mock_client.stacks.get.return_value = self.stack
         self.mock_client.events.list.return_value = [self.event0, self.event1]
@@ -1463,7 +1463,7 @@ class TestStackHookClear(TestStack):
     })
 
     def setUp(self):
-        super(TestStackHookClear, self).setUp()
+        super().setUp()
         self.cmd = stack.StackHookClear(self.app, None)
         self.mock_client.stacks.get.return_value = self.stack
         self.mock_client.resources.list.return_value = [self.resource]
@@ -1514,7 +1514,7 @@ class TestEnvironmentStackShow(TestStack):
     }
 
     def setUp(self):
-        super(TestEnvironmentStackShow, self).setUp()
+        super().setUp()
         self.cmd = stack.EnvironmentShowStack(self.app, None)
 
     def test_stack_environment_show(self):
diff --git a/heatclient/tests/unit/osc/v1/test_stack_failures.py b/heatclient/tests/unit/osc/v1/test_stack_failures.py
index 9cb56503..3199d6c9 100644
--- a/heatclient/tests/unit/osc/v1/test_stack_failures.py
+++ b/heatclient/tests/unit/osc/v1/test_stack_failures.py
@@ -24,7 +24,7 @@ from heatclient.tests.unit.osc.v1 import fakes as orchestration_fakes
 class ListStackFailuresTest(orchestration_fakes.TestOrchestrationv1):
 
     def setUp(self):
-        super(ListStackFailuresTest, self).setUp()
+        super().setUp()
         self.cmd = stack_failures.ListStackFailures(self.app, None)
         self.cmd.heat_client = self.app.client_manager.orchestration
         self.stack_client = self.app.client_manager.orchestration.stacks
diff --git a/heatclient/tests/unit/osc/v1/test_template.py b/heatclient/tests/unit/osc/v1/test_template.py
index 0d4fb9ab..1c57bf50 100644
--- a/heatclient/tests/unit/osc/v1/test_template.py
+++ b/heatclient/tests/unit/osc/v1/test_template.py
@@ -22,7 +22,7 @@ from heatclient.v1 import template_versions
 
 class TestTemplate(fakes.TestOrchestrationv1):
     def setUp(self):
-        super(TestTemplate, self).setUp()
+        super().setUp()
         self.mock_client = self.app.client_manager.orchestration
         self.template_versions = self.mock_client.template_versions
 
@@ -72,7 +72,7 @@ class TestTemplateFunctionList(TestTemplate):
     ]
 
     def setUp(self):
-        super(TestTemplateFunctionList, self).setUp()
+        super().setUp()
         self.tv1 = template_versions.TemplateVersion(None, self.defaults[0])
         self.tv2 = template_versions.TemplateVersion(None, self.defaults[1])
         self.tv_with_cf = template_versions.TemplateVersion(
@@ -124,7 +124,7 @@ class TestTemplateValidate(TestTemplate):
     }
 
     def setUp(self):
-        super(TestTemplateValidate, self).setUp()
+        super().setUp()
         self.stack_client = self.app.client_manager.orchestration.stacks
         self.stack_client.validate = mock.MagicMock(return_value={})
         self.cmd = template.Validate(self.app, None)
diff --git a/heatclient/tests/unit/test_actions.py b/heatclient/tests/unit/test_actions.py
index 512d5665..a0351bd9 100644
--- a/heatclient/tests/unit/test_actions.py
+++ b/heatclient/tests/unit/test_actions.py
@@ -20,11 +20,11 @@ from heatclient.v1 import actions
 class ActionManagerTest(testtools.TestCase):
 
     def setUp(self):
-        super(ActionManagerTest, self).setUp()
+        super().setUp()
 
     def _base_test(self, expect_args, expect_kwargs):
 
-        class FakeAPI(object):
+        class FakeAPI:
             """Fake API and ensure request url is correct."""
 
             def json_request(self, *args, **kwargs):
diff --git a/heatclient/tests/unit/test_build_info.py b/heatclient/tests/unit/test_build_info.py
index 99330e0a..d7ace027 100644
--- a/heatclient/tests/unit/test_build_info.py
+++ b/heatclient/tests/unit/test_build_info.py
@@ -24,7 +24,7 @@ from heatclient.v1 import build_info
 
 class BuildInfoManagerTest(testtools.TestCase):
     def setUp(self):
-        super(BuildInfoManagerTest, self).setUp()
+        super().setUp()
         self.client = mock.Mock()
         self.client.get.return_value = fakes.FakeHTTPResponse(
             200,
diff --git a/heatclient/tests/unit/test_common_http.py b/heatclient/tests/unit/test_common_http.py
index eb124ca8..d8127608 100644
--- a/heatclient/tests/unit/test_common_http.py
+++ b/heatclient/tests/unit/test_common_http.py
@@ -1,4 +1,3 @@
-# -*- coding:utf-8 -*-
 # Licensed under the Apache License, Version 2.0 (the "License");
 # you may not use this file except in compliance with the License.
 # You may obtain a copy of the License at
@@ -557,12 +556,12 @@ class HttpClientTest(testtools.TestCase):
         client = http.HTTPClient('http://somewhere')
         client.log_curl_request("GET", '', kwargs=kwargs)
         mock_log.assert_called_once_with(
-            u"curl -g -i -X GET -H 'Key: foo㊎' http://somewhere")
+            "curl -g -i -X GET -H 'Key: foo㊎' http://somewhere")
 
 
 class SessionClientTest(testtools.TestCase):
     def setUp(self):
-        super(SessionClientTest, self).setUp()
+        super().setUp()
         self.request = mock.patch.object(adapter.LegacyJsonAdapter,
                                          'request').start()
 
diff --git a/heatclient/tests/unit/test_event_utils.py b/heatclient/tests/unit/test_event_utils.py
index bcc8dbae..b338dc1d 100644
--- a/heatclient/tests/unit/test_event_utils.py
+++ b/heatclient/tests/unit/test_event_utils.py
@@ -19,7 +19,7 @@ from heatclient.v1 import events as hc_ev
 from heatclient.v1 import resources as hc_res
 
 
-class FakeWebSocket(object):
+class FakeWebSocket:
 
     def __init__(self, events):
         self.events = events
@@ -64,10 +64,11 @@ class ShellTestEventUtils(testtools.TestCase):
     def _mock_stack_event(event_id, stack_name,
                           stack_status='CREATE_COMPLETE'):
         stack_id = 'abcdef'
-        ev_info = {"links": [{"href": "http://heat/foo", "rel": "self"},
-                             {"href": "http://heat/stacks/%s/%s" % (stack_name,
-                                                                    stack_id),
-                              "rel": "stack"}],
+        ev_info = {"links": [
+                        {"href": "http://heat/foo", "rel": "self"},
+                        {"href": "http://heat/stacks/{}/{}".format(stack_name,
+                                                                   stack_id),
+                         "rel": "stack"}],
                    "logical_resource_id": stack_name,
                    "physical_resource_id": stack_id,
                    "resource_name": stack_name,
diff --git a/heatclient/tests/unit/test_events.py b/heatclient/tests/unit/test_events.py
index 289b3e09..62066df9 100644
--- a/heatclient/tests/unit/test_events.py
+++ b/heatclient/tests/unit/test_events.py
@@ -106,7 +106,7 @@ class EventManagerTest(testtools.TestCase):
                   'resource_name': 'testresource',
                   'event_id': '1'}
 
-        class FakeAPI(object):
+        class FakeAPI:
             """Fake API and ensure request url is correct."""
 
             def json_request(self, *args, **kwargs):
@@ -133,7 +133,7 @@ class EventManagerTest(testtools.TestCase):
                   'resource_name': '\u5de5\u4f5c',
                   'event_id': '1'}
 
-        class FakeAPI(object):
+        class FakeAPI:
             """Fake API and ensure request url is correct."""
 
             def json_request(self, *args, **kwargs):
diff --git a/heatclient/tests/unit/test_resource_formatter.py b/heatclient/tests/unit/test_resource_formatter.py
index f69f6490..631116e3 100644
--- a/heatclient/tests/unit/test_resource_formatter.py
+++ b/heatclient/tests/unit/test_resource_formatter.py
@@ -84,7 +84,7 @@ OS::Heat::RandomString" ];
 '''
 
     def setUp(self):
-        super(TestStackResourceListDotFormat, self).setUp()
+        super().setUp()
         self.resource_client = self.app.client_manager.orchestration.resources
         self.cmd = resource.ResourceList(self.app, None)
         with open(self.response_path) as f:
diff --git a/heatclient/tests/unit/test_resource_types.py b/heatclient/tests/unit/test_resource_types.py
index 92d1c497..c7010b3d 100644
--- a/heatclient/tests/unit/test_resource_types.py
+++ b/heatclient/tests/unit/test_resource_types.py
@@ -23,7 +23,7 @@ class ResourceTypeManagerTest(testtools.TestCase):
 
     def _base_test(self, expect, key):
 
-        class FakeAPI(object):
+        class FakeAPI:
             """Fake API and ensure request url is correct."""
 
             def get(self, *args, **kwargs):
@@ -60,11 +60,11 @@ class ResourceTypeManagerTest(testtools.TestCase):
         key = 'resource_types'
         expect = ('GET', '/resource_types')
 
-        class FakeResponse(object):
+        class FakeResponse:
             def json(self):
                 return {key: {}}
 
-        class FakeClient(object):
+        class FakeClient:
             def get(self, *args, **kwargs):
                 assert ('GET', args[0]) == expect
                 return FakeResponse()
diff --git a/heatclient/tests/unit/test_resources.py b/heatclient/tests/unit/test_resources.py
index f7b9dba5..823b8f60 100644
--- a/heatclient/tests/unit/test_resources.py
+++ b/heatclient/tests/unit/test_resources.py
@@ -21,7 +21,7 @@ from heatclient.common import utils
 from heatclient.v1 import resources
 
 
-class FakeAPI(object):
+class FakeAPI:
     """Fake API and ensure request url is correct."""
 
     def __init__(self, expect, key):
@@ -105,11 +105,11 @@ class ResourceManagerTest(testtools.TestCase):
     def _test_list(self, fields, expect):
         key = 'resources'
 
-        class FakeResponse(object):
+        class FakeResponse:
             def json(self):
                 return {key: {}}
 
-        class FakeClient(object):
+        class FakeClient:
             def get(self, *args, **kwargs):
                 assert args[0] == expect
                 return FakeResponse()
@@ -161,7 +161,7 @@ class ResourceManagerTest(testtools.TestCase):
         expect = ('GET', '/resource_types/testresource/template')
         key = None
 
-        class FakeAPI(object):
+        class FakeAPI:
             """Fake API and ensure request url is correct."""
 
             def get(self, *args, **kwargs):
diff --git a/heatclient/tests/unit/test_service.py b/heatclient/tests/unit/test_service.py
index 18c59c88..28bba51a 100644
--- a/heatclient/tests/unit/test_service.py
+++ b/heatclient/tests/unit/test_service.py
@@ -21,14 +21,14 @@ from heatclient.v1 import services
 
 class ManageServiceTest(testtools.TestCase):
     def setUp(self):
-        super(ManageServiceTest, self).setUp()
+        super().setUp()
 
     def test_service_list(self):
-        class FakeResponse(object):
+        class FakeResponse:
             def json(self):
                 return {'services': []}
 
-        class FakeClient(object):
+        class FakeClient:
             def get(self, *args, **kwargs):
                 assert args[0] == ('/services')
                 return FakeResponse()
@@ -37,7 +37,7 @@ class ManageServiceTest(testtools.TestCase):
         self.assertEqual([], manager.list())
 
     def test_service_list_403(self):
-        class FakeClient403(object):
+        class FakeClient403:
 
             def get(self, *args, **kwargs):
                 assert args[0] == ('/services')
@@ -48,7 +48,7 @@ class ManageServiceTest(testtools.TestCase):
                           manager.list)
 
     def test_service_list_503(self):
-        class FakeClient503(object):
+        class FakeClient503:
             def get(self, *args, **kwargs):
                 assert args[0] == ('/services')
                 raise exc.HTTPServiceUnavailable()
diff --git a/heatclient/tests/unit/test_shell.py b/heatclient/tests/unit/test_shell.py
index e4cf2ca6..d6a378a9 100644
--- a/heatclient/tests/unit/test_shell.py
+++ b/heatclient/tests/unit/test_shell.py
@@ -69,7 +69,7 @@ class TestCase(testtools.TestCase):
     tokenid = uuid.uuid4().hex
 
     def setUp(self):
-        super(TestCase, self).setUp()
+        super().setUp()
         self.requests = self.useFixture(rm_fixture.Fixture())
         # httpretty doesn't work as expected if http proxy environmen
         # variable is set.
@@ -192,7 +192,7 @@ class TestCase(testtools.TestCase):
              "logical_resource_id": "myDeployment",
              "physical_resource_id": "bce15ec4-8919-4a02-8a90-680960fb3731",
              "resource_name": rn,
-             "resource_status": "%s_%s" % (action, final_state),
+             "resource_status": "{}_{}".format(action, final_state),
              "resource_status_reason": "state changed"}]}
 
         if resource_name is None:
@@ -227,7 +227,7 @@ class TestCase(testtools.TestCase):
                  "logical_resource_id": "aResource",
                  "physical_resource_id": 'foo3',
                  "resource_name": stack_name,
-                 "resource_status": "%s_%s" % (action, final_state),
+                 "resource_status": "{}_{}".format(action, final_state),
                  "resource_status_reason": "state changed"})
 
         return resp_dict
@@ -320,7 +320,7 @@ class ShellParamValidationTest(TestCase):
 
         if self.with_tmpl:
             template_file = os.path.join(TEST_VAR_DIR, 'minimal.template')
-            cmd = '%s --template-file=%s ' % (self.command, template_file)
+            cmd = '{} --template-file={} '.format(self.command, template_file)
 
         self.shell_error(cmd, self.err, exception=exc.CommandError)
 
@@ -379,7 +379,7 @@ class ShellBase(TestCase):
     (JSON, RAW, SESSION) = ('json', 'raw', 'session')
 
     def setUp(self):
-        super(ShellBase, self).setUp()
+        super().setUp()
         self._calls = {self.JSON: [], self.RAW: [], self.SESSION: []}
         self._results = {self.JSON: [], self.RAW: [], self.SESSION: []}
         self.useFixture(fixtures.MockPatchObject(
@@ -406,7 +406,7 @@ class ShellBase(TestCase):
         http.HTTPClient.json_request.assert_has_calls(self._calls[self.JSON])
         http.HTTPClient.raw_request.assert_has_calls(self._calls[self.RAW])
         http.SessionClient.request.assert_has_calls(self._calls[self.SESSION])
-        super(ShellBase, self).tearDown()
+        super().tearDown()
 
     def shell(self, argstr):
         orig = sys.stdout
@@ -509,7 +509,7 @@ class ShellTestNoMoxBase(TestCase):
     # NOTE(dhu):  This class is reserved for no Mox usage.  Instead,
     # use requests_mock to expose errors from json_request.
     def setUp(self):
-        super(ShellTestNoMoxBase, self).setUp()
+        super().setUp()
         self._set_fake_env()
 
     def _set_fake_env(self):
@@ -614,7 +614,7 @@ class ShellTestNoMoxV3(ShellTestNoMox):
 class ShellTestEndpointType(TestCase):
 
     def setUp(self):
-        super(ShellTestEndpointType, self).setUp()
+        super().setUp()
         self.useFixture(fixtures.MockPatchObject(http,
                                                  '_construct_http_client'))
         self.useFixture(fixtures.MockPatchObject(heatclient.v1.shell,
@@ -687,7 +687,7 @@ class ShellTestEndpointType(TestCase):
 class ShellTestCommon(ShellBase):
 
     def setUp(self):
-        super(ShellTestCommon, self).setUp()
+        super().setUp()
         self.client = http.SessionClient
         self.set_fake_env(FAKE_ENV_KEYSTONE_V2)
 
@@ -754,7 +754,7 @@ class ShellTestCommon(ShellBase):
 class ShellTestUserPass(ShellBase):
 
     def setUp(self):
-        super(ShellTestUserPass, self).setUp()
+        super().setUp()
         if self.client is None:
             self.client = http.SessionClient
         self._set_fake_env()
@@ -932,7 +932,7 @@ class ShellTestUserPass(ShellBase):
                 "description": "test output 2",
             },
             {
-                "output_value": u"test\u2665",
+                "output_value": "test\u2665",
                 "output_key": "output_uni",
                 "description": "test output unicode",
             },
@@ -983,7 +983,7 @@ class ShellTestUserPass(ShellBase):
     def test_template_show_cfn_unicode(self):
         self.register_keystone_auth_fixture()
         resp_dict = {"AWSTemplateFormatVersion": "2010-09-09",
-                     "Description": u"test\u2665",
+                     "Description": "test\u2665",
                      "Outputs": {},
                      "Resources": {},
                      "Parameters": {}}
@@ -2485,7 +2485,7 @@ class ShellTestUserPass(ShellBase):
 class ShellTestActions(ShellBase):
 
     def setUp(self):
-        super(ShellTestActions, self).setUp()
+        super().setUp()
         self.set_fake_env(FAKE_ENV_KEYSTONE_V2)
 
     def test_stack_cancel_update(self):
@@ -2576,7 +2576,7 @@ class ShellTestActions(ShellBase):
 class ShellTestEvents(ShellBase):
 
     def setUp(self):
-        super(ShellTestEvents, self).setUp()
+        super().setUp()
         self.set_fake_env(FAKE_ENV_KEYSTONE_V2)
 
     scenarios = [
@@ -2597,13 +2597,13 @@ class ShellTestEvents(ShellBase):
         stack_id = 'teststack/1'
         resource_name = 'testresource/1'
         self.mock_request_get(
-            '/stacks/%s/resources/%s/events?sort_dir=asc' % (
+            '/stacks/{}/resources/{}/events?sort_dir=asc'.format(
                 parse.quote(stack_id),
                 parse.quote(encodeutils.safe_encode(
                     resource_name))),
             resp_dict)
 
-        event_list_text = self.shell('event-list {0} --resource {1}'.format(
+        event_list_text = self.shell('event-list {} --resource {}'.format(
                                      stack_id, resource_name))
 
         required = [
@@ -2636,7 +2636,7 @@ class ShellTestEvents(ShellBase):
         self.mock_request_get('/stacks/%s/events?sort_dir=asc' % stack_id,
                               resp_dict)
 
-        event_list_text = self.shell('event-list {0} --format log'.format(
+        event_list_text = self.shell('event-list {} --format log'.format(
             stack_id))
 
         expected = ('2013-12-05 14:14:31 [aResource]: '
@@ -2678,7 +2678,7 @@ class ShellTestEvents(ShellBase):
             ),
             resp_dict)
 
-        event_list_text = self.shell('event-show {0} {1} {2}'.format(
+        event_list_text = self.shell('event-show {} {} {}'.format(
                                      stack_id, resource_name,
                                      self.event_id_one))
 
@@ -2711,7 +2711,7 @@ class ShellTestEvents(ShellBase):
 
 class ShellTestEventsNested(ShellBase):
     def setUp(self):
-        super(ShellTestEventsNested, self).setUp()
+        super().setUp()
         self.set_fake_env(FAKE_ENV_KEYSTONE_V2)
 
     def test_shell_nested_depth_invalid_xor(self):
@@ -2721,7 +2721,7 @@ class ShellTestEventsNested(ShellBase):
 
         error = self.assertRaises(
             exc.CommandError, self.shell,
-            'event-list {0} --resource {1} --nested-depth 5'.format(
+            'event-list {} --resource {} --nested-depth 5'.format(
                 stack_id, resource_name))
         self.assertIn('--nested-depth cannot be specified with --resource',
                       str(error))
@@ -2731,7 +2731,7 @@ class ShellTestEventsNested(ShellBase):
         stack_id = 'teststack/1'
         error = self.assertRaises(
             exc.CommandError, self.shell,
-            'event-list {0} --nested-depth Z'.format(stack_id))
+            'event-list {} --nested-depth Z'.format(stack_id))
         self.assertIn('--nested-depth invalid value Z', str(error))
 
     def test_shell_nested_depth_zero(self):
@@ -2946,7 +2946,7 @@ class ShellTestEventsNested(ShellBase):
 
 class ShellTestHookFunctions(ShellBase):
     def setUp(self):
-        super(ShellTestHookFunctions, self).setUp()
+        super().setUp()
         self.set_fake_env(FAKE_ENV_KEYSTONE_V2)
 
     def _stub_stack_response(self, stack_id, action='CREATE',
@@ -2955,7 +2955,7 @@ class ShellTestHookFunctions(ShellBase):
         resp_dict = {"stack": {
             "id": stack_id.split("/")[1],
             "stack_name": stack_id.split("/")[0],
-            "stack_status": '%s_%s' % (action, status),
+            "stack_status": '{}_{}'.format(action, status),
             "creation_time": "2014-01-06T16:14:00Z",
         }}
         self.mock_request_get('/stacks/teststack/1', resp_dict)
@@ -3091,7 +3091,7 @@ class ShellTestHookFunctions(ShellBase):
 class ShellTestResources(ShellBase):
 
     def setUp(self):
-        super(ShellTestResources, self).setUp()
+        super().setUp()
         self.set_fake_env(FAKE_ENV_KEYSTONE_V2)
 
     def _test_resource_list(self, with_resource_name):
@@ -3113,7 +3113,7 @@ class ShellTestResources(ShellBase):
         stack_id = 'teststack/1'
         self.mock_request_get('/stacks/%s/resources' % stack_id, resp_dict)
 
-        resource_list_text = self.shell('resource-list {0}'.format(stack_id))
+        resource_list_text = self.shell('resource-list {}'.format(stack_id))
 
         required = [
             'physical_resource_id',
@@ -3147,7 +3147,7 @@ class ShellTestResources(ShellBase):
         stack_id = 'teststack/1'
         self.mock_request_get('/stacks/%s/resources' % stack_id, resp_dict)
 
-        resource_list_text = self.shell('resource-list {0}'.format(stack_id))
+        resource_list_text = self.shell('resource-list {}'.format(stack_id))
 
         self.assertEqual('''\
 +---------------+----------------------+---------------+-----------------+\
@@ -3174,10 +3174,10 @@ class ShellTestResources(ShellBase):
             }],
         }]}
         stack_id = 'teststack/1'
-        self.mock_request_get('/stacks/%s/resources?%s' % (
+        self.mock_request_get('/stacks/{}/resources?{}'.format(
             stack_id, query_args), resp_dict)
 
-        shell_cmd = 'resource-list %s %s' % (stack_id, cmd_args)
+        shell_cmd = 'resource-list {} {}'.format(stack_id, cmd_args)
 
         resource_list_text = self.shell(shell_cmd)
 
@@ -3234,7 +3234,7 @@ class ShellTestResources(ShellBase):
             ), resp_dict)
 
         resource_show_text = self.shell(
-            'resource-show {0} {1} --with-attr attr_a '
+            'resource-show {} {} --with-attr attr_a '
             '--with-attr attr_b'.format(
                 stack_id, resource_name))
 
@@ -3297,7 +3297,7 @@ class ShellTestResources(ShellBase):
         )
 
         text = self.shell(
-            'resource-signal {0} {1}'.format(stack_id, resource_name))
+            'resource-signal {} {}'.format(stack_id, resource_name))
         self.assertEqual("", text)
 
     def test_resource_signal_no_json(self):
@@ -3307,7 +3307,7 @@ class ShellTestResources(ShellBase):
 
         error = self.assertRaises(
             exc.CommandError, self.shell,
-            'resource-signal {0} {1} -D [2'.format(
+            'resource-signal {} {} -D [2'.format(
                 stack_id, resource_name))
         self.assertIn('Data should be in JSON format', str(error))
 
@@ -3318,7 +3318,7 @@ class ShellTestResources(ShellBase):
 
         error = self.assertRaises(
             exc.CommandError, self.shell,
-            'resource-signal {0} {1} -D "message"'.format(
+            'resource-signal {} {} -D "message"'.format(
                 stack_id, resource_name))
         self.assertEqual('Data should be a JSON dict', str(error))
 
@@ -3329,7 +3329,7 @@ class ShellTestResources(ShellBase):
 
         error = self.assertRaises(
             exc.CommandError, self.shell,
-            'resource-signal {0} {1} -D "message" -f foo'.format(
+            'resource-signal {} {} -D "message" -f foo'.format(
                 stack_id, resource_name))
         self.assertEqual('Can only specify one of data and data-file',
                          str(error))
@@ -3353,7 +3353,7 @@ class ShellTestResources(ShellBase):
             data_file.write(b'{"message":"Content"}')
             data_file.flush()
             text = self.shell(
-                'resource-signal {0} {1} -f {2}'.format(
+                'resource-signal {} {} -f {}'.format(
                     stack_id, resource_name, data_file.name))
             self.assertEqual("", text)
 
@@ -3374,7 +3374,7 @@ class ShellTestResources(ShellBase):
                   'resource_status_reason': 'Any'})
 
         text = self.shell(
-            'resource-mark-unhealthy {0} {1} Any'.format(
+            'resource-mark-unhealthy {} {} Any'.format(
                 stack_id, resource_name))
         self.assertEqual("", text)
 
@@ -3395,7 +3395,7 @@ class ShellTestResources(ShellBase):
                   'resource_status_reason': 'Any'})
 
         text = self.shell(
-            'resource-mark-unhealthy --reset {0} {1} Any'.format(
+            'resource-mark-unhealthy --reset {} {} Any'.format(
                 stack_id, resource_name))
         self.assertEqual("", text)
 
@@ -3416,14 +3416,14 @@ class ShellTestResources(ShellBase):
                   'resource_status_reason': ''})
 
         text = self.shell(
-            'resource-mark-unhealthy {0} {1}'.format(
+            'resource-mark-unhealthy {} {}'.format(
                 stack_id, resource_name))
         self.assertEqual("", text)
 
 
 class ShellTestResourceTypes(ShellBase):
     def setUp(self):
-        super(ShellTestResourceTypes, self).setUp()
+        super().setUp()
         self.set_fake_env(FAKE_ENV_KEYSTONE_V3)
 
     def test_resource_type_template_yaml(self):
@@ -3476,7 +3476,7 @@ class ShellTestResourceTypes(ShellBase):
 class ShellTestConfig(ShellBase):
 
     def setUp(self):
-        super(ShellTestConfig, self).setUp()
+        super().setUp()
         self._set_fake_env()
 
     def _set_fake_env(self):
@@ -3621,7 +3621,7 @@ class ShellTestConfig(ShellBase):
 class ShellTestDeployment(ShellBase):
 
     def setUp(self):
-        super(ShellTestDeployment, self).setUp()
+        super().setUp()
         self.client = http.SessionClient
         self._set_fake_env()
 
@@ -3928,7 +3928,7 @@ class ShellTestDeployment(ShellBase):
 class ShellTestBuildInfo(ShellBase):
 
     def setUp(self):
-        super(ShellTestBuildInfo, self).setUp()
+        super().setUp()
         self._set_fake_env()
 
     def _set_fake_env(self):
@@ -3963,7 +3963,7 @@ class ShellTestToken(ShellTestUserPass):
     # Rerun all ShellTestUserPass test with token auth
     def setUp(self):
         self.token = 'a_token'
-        super(ShellTestToken, self).setUp()
+        super().setUp()
 
     def _set_fake_env(self):
         fake_env = {
@@ -3986,10 +3986,10 @@ class ShellTestUserPassKeystoneV3(ShellTestUserPass):
         self.set_fake_env(FAKE_ENV_KEYSTONE_V3)
 
 
-class StandaloneTokenMixin(object):
+class StandaloneTokenMixin:
     def setUp(self):
         self.token = 'a_token'
-        super(StandaloneTokenMixin, self).setUp()
+        super().setUp()
         self.client = http.HTTPClient
 
     def _set_fake_env(self):
@@ -4067,7 +4067,7 @@ class ShellTestStandaloneTokenArgs(StandaloneTokenMixin, ShellTestNoMoxBase):
 class MockShellBase(TestCase):
 
     def setUp(self):
-        super(MockShellBase, self).setUp()
+        super().setUp()
         self.jreq_mock = self.patch(
             'heatclient.common.http.HTTPClient.json_request')
         self.session_jreq_mock = self.patch(
@@ -4100,7 +4100,7 @@ class MockShellBase(TestCase):
 class MockShellTestUserPass(MockShellBase):
 
     def setUp(self):
-        super(MockShellTestUserPass, self).setUp()
+        super().setUp()
         self._set_fake_env()
 
     def _set_fake_env(self):
@@ -4174,7 +4174,7 @@ class MockShellTestToken(MockShellTestUserPass):
     # Rerun all ShellTestUserPass test with token auth
     def setUp(self):
         self.token = 'a_token'
-        super(MockShellTestToken, self).setUp()
+        super().setUp()
 
     def _set_fake_env(self):
         fake_env = {
@@ -4203,7 +4203,7 @@ class MockShellTestStandaloneToken(MockShellTestUserPass):
     # specify --os-no-client-auth, a token and Heat endpoint
     def setUp(self):
         self.token = 'a_token'
-        super(MockShellTestStandaloneToken, self).setUp()
+        super().setUp()
 
     def _set_fake_env(self):
         fake_env = {
@@ -4224,7 +4224,7 @@ class MockShellTestStandaloneToken(MockShellTestUserPass):
 class ShellTestManageService(ShellBase):
 
     def setUp(self):
-        super(ShellTestManageService, self).setUp()
+        super().setUp()
         self.set_fake_env(FAKE_ENV_KEYSTONE_V2)
 
     def _set_fake_env(self):
diff --git a/heatclient/tests/unit/test_software_configs.py b/heatclient/tests/unit/test_software_configs.py
index e55bb400..5eb53551 100644
--- a/heatclient/tests/unit/test_software_configs.py
+++ b/heatclient/tests/unit/test_software_configs.py
@@ -21,7 +21,7 @@ from heatclient.v1 import software_configs
 class SoftwareConfigTest(testtools.TestCase):
 
     def setUp(self):
-        super(SoftwareConfigTest, self).setUp()
+        super().setUp()
         config_id = 'bca6871d-86c0-4aff-b792-58a1f6947b57'
         self.config = software_configs.SoftwareConfig(mock.MagicMock(),
                                                       info={'id': config_id})
@@ -45,7 +45,7 @@ class SoftwareConfigTest(testtools.TestCase):
 class SoftwareConfigManagerTest(testtools.TestCase):
 
     def setUp(self):
-        super(SoftwareConfigManagerTest, self).setUp()
+        super().setUp()
         self.manager = software_configs.SoftwareConfigManager(mock.MagicMock())
 
     def test_list(self):
diff --git a/heatclient/tests/unit/test_software_deployments.py b/heatclient/tests/unit/test_software_deployments.py
index 046fb2cc..688e9b06 100644
--- a/heatclient/tests/unit/test_software_deployments.py
+++ b/heatclient/tests/unit/test_software_deployments.py
@@ -21,7 +21,7 @@ from heatclient.v1 import software_deployments
 class SoftwareDeploymentTest(testtools.TestCase):
 
     def setUp(self):
-        super(SoftwareDeploymentTest, self).setUp()
+        super().setUp()
         deployment_id = 'bca6871d-86c0-4aff-b792-58a1f6947b57'
         self.deployment = software_deployments.SoftwareDeployment(
             mock.MagicMock(), info={'id': deployment_id})
@@ -48,7 +48,7 @@ class SoftwareDeploymentTest(testtools.TestCase):
 class SoftwareDeploymentManagerTest(testtools.TestCase):
 
     def setUp(self):
-        super(SoftwareDeploymentManagerTest, self).setUp()
+        super().setUp()
         self.manager = software_deployments.SoftwareDeploymentManager(
             mock.MagicMock())
 
diff --git a/heatclient/tests/unit/test_stacks.py b/heatclient/tests/unit/test_stacks.py
index d1c6a1c9..02627cfd 100644
--- a/heatclient/tests/unit/test_stacks.py
+++ b/heatclient/tests/unit/test_stacks.py
@@ -26,7 +26,7 @@ def mock_stack(manager, stack_name, stack_id):
         "id": stack_id,
         "stack_name": stack_name,
         "links": [{
-            "href": "http://192.0.2.1:8004/v1/1234/stacks/%s/%s" % (
+            "href": "http://192.0.2.1:8004/v1/1234/stacks/{}/{}".format(
                 stack_name, stack_id),
             "rel": "self"}],
         "description": "No description",
@@ -54,7 +54,7 @@ class StackStatusActionTest(testtools.TestCase):
     ])
 
     def test_status_action(self):
-        stack_status = '%s_%s' % (self.action, self.status)
+        stack_status = '{}_{}'.format(self.action, self.status)
         stack = mock_stack(None, 'stack_1', 'abcd1234')
         stack.stack_status = stack_status
         self.assertEqual(self.action, stack.action)
@@ -346,7 +346,7 @@ class StackManagerPaginationTest(testtools.TestCase):
 class StackManagerValidateTest(testtools.TestCase):
 
     def setUp(self):
-        super(StackManagerValidateTest, self).setUp()
+        super().setUp()
 
         self.mock_response = mock.MagicMock()
         self.mock_response.json.return_value = {'result': 'fake_response'}
diff --git a/heatclient/tests/unit/test_template_utils.py b/heatclient/tests/unit/test_template_utils.py
index 83a75851..4bdde49d 100644
--- a/heatclient/tests/unit/test_template_utils.py
+++ b/heatclient/tests/unit/test_template_utils.py
@@ -716,7 +716,7 @@ class TestGetTemplateContents(testtools.TestCase):
 
     def check_non_utf8_content(self, filename, content):
         base_url = 'file:///tmp'
-        url = '%s/%s' % (base_url, filename)
+        url = '{}/{}'.format(base_url, filename)
         template = {'resources':
                     {'one_init':
                      {'type': 'OS::Heat::CloudConfig',
diff --git a/heatclient/tests/unit/test_template_versions.py b/heatclient/tests/unit/test_template_versions.py
index fe3cd098..076b88af 100644
--- a/heatclient/tests/unit/test_template_versions.py
+++ b/heatclient/tests/unit/test_template_versions.py
@@ -19,17 +19,17 @@ from heatclient.v1 import template_versions
 class TemplateVersionManagerTest(testtools.TestCase):
 
     def setUp(self):
-        super(TemplateVersionManagerTest, self).setUp()
+        super().setUp()
 
     def test_list_versions(self):
         expect = ('GET', '/template_versions')
 
-        class FakeResponse(object):
+        class FakeResponse:
             def json(self):
                 return {'template_versions': [{'version': '2013-05-23',
                                                'type': 'hot'}]}
 
-        class FakeClient(object):
+        class FakeClient:
             def get(self, *args, **kwargs):
                 assert ('GET', args[0]) == expect
                 return FakeResponse()
@@ -43,11 +43,11 @@ class TemplateVersionManagerTest(testtools.TestCase):
         expect = ('GET', '/template_versions/heat_template_version.2015-04-30'
                          '/functions')
 
-        class FakeResponse(object):
+        class FakeResponse:
             def json(self):
                 return {'template_functions': [{'function': 'get_attr'}]}
 
-        class FakeClient(object):
+        class FakeClient:
             def get(self, *args, **kwargs):
                 assert ('GET', args[0]) == expect
                 return FakeResponse()
diff --git a/heatclient/tests/unit/test_utils.py b/heatclient/tests/unit/test_utils.py
index 24454e34..4b576a0f 100644
--- a/heatclient/tests/unit/test_utils.py
+++ b/heatclient/tests/unit/test_utils.py
@@ -146,7 +146,7 @@ class ShellTest(testtools.TestCase):
         self.assertEqual('{\n  "foo": "bar"\n}',
                          utils.json_formatter({"foo": "bar"}))
         self.assertEqual('{\n  "Uni": "test\u2665"\n}',
-                         utils.json_formatter({"Uni": u"test\u2665"}))
+                         utils.json_formatter({"Uni": "test\u2665"}))
 
     def test_yaml_formatter(self):
         self.assertEqual('null\n...\n', utils.yaml_formatter(None))
@@ -162,8 +162,8 @@ class ShellTest(testtools.TestCase):
         self.assertEqual(
             'one two three four five six seven eight nine ten eleven\ntwelve',
             utils.text_wrap_formatter(
-                ('one two three four five six seven '
-                 'eight nine ten eleven twelve')))
+                'one two three four five six seven '
+                'eight nine ten eleven twelve'))
 
     def test_newline_list_formatter(self):
         self.assertEqual('', utils.newline_list_formatter(None))
@@ -380,7 +380,7 @@ class ShellTestParameterFiles(testtools.TestCase):
 class TestURLFunctions(testtools.TestCase):
 
     def setUp(self):
-        super(TestURLFunctions, self).setUp()
+        super().setUp()
         self.m = mock.MagicMock()
 
         self.addCleanup(self.m.UnsetStubs)
diff --git a/heatclient/tests/unit/v1/test_hooks.py b/heatclient/tests/unit/v1/test_hooks.py
index 90cef7c4..a24b6324 100644
--- a/heatclient/tests/unit/v1/test_hooks.py
+++ b/heatclient/tests/unit/v1/test_hooks.py
@@ -21,7 +21,7 @@ import heatclient.v1.shell as shell
 
 class TestHooks(testtools.TestCase):
     def setUp(self):
-        super(TestHooks, self).setUp()
+        super().setUp()
         self.client = mock.Mock()
         nested_stack = mock.Mock()
         self.client.resources.get = mock.Mock(name='thingy',
diff --git a/heatclient/v1/client.py b/heatclient/v1/client.py
index 3d3c1e9e..69b10e2c 100644
--- a/heatclient/v1/client.py
+++ b/heatclient/v1/client.py
@@ -26,7 +26,7 @@ from heatclient.v1 import stacks
 from heatclient.v1 import template_versions
 
 
-class Client(object):
+class Client:
     """Client for the Heat v1 API.
 
     :param string endpoint: A user-supplied endpoint URL for the heat
diff --git a/heatclient/v1/events.py b/heatclient/v1/events.py
index 94276916..c3276b54 100644
--- a/heatclient/v1/events.py
+++ b/heatclient/v1/events.py
@@ -61,7 +61,7 @@ class EventManager(stacks.StackChildManager):
             url = '/stacks/%s/events' % stack_id
         else:
             stack_id = self._resolve_stack_id(stack_id)
-            url = '/stacks/%s/resources/%s/events' % (
+            url = '/stacks/{}/resources/{}/events'.format(
                 parse.quote(stack_id),
                 parse.quote(encodeutils.safe_encode(resource_name)))
         if params:
@@ -79,7 +79,7 @@ class EventManager(stacks.StackChildManager):
         :param event_id: ID of event to get the details for
         """
         stack_id = self._resolve_stack_id(stack_id)
-        url_str = '/stacks/%s/resources/%s/events/%s' % (
+        url_str = '/stacks/{}/resources/{}/events/{}'.format(
                   parse.quote(stack_id),
                   parse.quote(encodeutils.safe_encode(resource_name)),
                   parse.quote(event_id, ''))
diff --git a/heatclient/v1/resource_types.py b/heatclient/v1/resource_types.py
index 4073dc18..0a66ae59 100644
--- a/heatclient/v1/resource_types.py
+++ b/heatclient/v1/resource_types.py
@@ -65,7 +65,7 @@ class ResourceTypeManager(base.BaseManager):
         :param resource_type: name of the resource type to get the details for
         :param with_description: return result with description or not
         """
-        url_str = '/%s/%s' % (
+        url_str = '/{}/{}'.format(
                   self.KEY,
                   parse.quote(encodeutils.safe_encode(resource_type)))
         resp = self.client.get(url_str,
@@ -74,7 +74,7 @@ class ResourceTypeManager(base.BaseManager):
         return body
 
     def generate_template(self, resource_type, template_type='cfn'):
-        url_str = '/%s/%s/template' % (
+        url_str = '/{}/{}/template'.format(
                   self.KEY,
                   parse.quote(encodeutils.safe_encode(resource_type)))
         if template_type:
diff --git a/heatclient/v1/resources.py b/heatclient/v1/resources.py
index 29e68873..fb020e6e 100644
--- a/heatclient/v1/resources.py
+++ b/heatclient/v1/resources.py
@@ -77,7 +77,7 @@ class ResourceManager(stacks.StackChildManager):
         :param with_attr: Attributes to show
         """
         stack_id = self._resolve_stack_id(stack_id)
-        url_str = '/stacks/%s/resources/%s' % (
+        url_str = '/stacks/{}/resources/{}'.format(
                   parse.quote(stack_id),
                   parse.quote(encodeutils.safe_encode(resource_name)))
         if with_attr:
@@ -95,7 +95,7 @@ class ResourceManager(stacks.StackChildManager):
         :param resource_name: ID of resource to get metadata for
         """
         stack_id = self._resolve_stack_id(stack_id)
-        url_str = '/stacks/%s/resources/%s/metadata' % (
+        url_str = '/stacks/{}/resources/{}/metadata'.format(
                   parse.quote(stack_id),
                   parse.quote(encodeutils.safe_encode(resource_name)))
         resp = self.client.get(url_str)
@@ -109,7 +109,7 @@ class ResourceManager(stacks.StackChildManager):
         :param resource_name: ID of resource to send signal to
         """
         stack_id = self._resolve_stack_id(stack_id)
-        url_str = '/stacks/%s/resources/%s/signal' % (
+        url_str = '/stacks/{}/resources/{}/signal'.format(
                   parse.quote(stack_id),
                   parse.quote(encodeutils.safe_encode(resource_name)))
         resp = self.client.post(url_str, data=data)
@@ -126,7 +126,7 @@ class ResourceManager(stacks.StackChildManager):
         :param resource_status_reason: Reason for resource status change.
         """
         stack_id = self._resolve_stack_id(stack_id)
-        url_str = '/stacks/%s/resources/%s' % (
+        url_str = '/stacks/{}/resources/{}'.format(
                   parse.quote(stack_id),
                   parse.quote(encodeutils.safe_encode(resource_name)))
         resp = self.client.patch(
diff --git a/heatclient/v1/shell.py b/heatclient/v1/shell.py
index f7e6fe2d..021d6b5d 100644
--- a/heatclient/v1/shell.py
+++ b/heatclient/v1/shell.py
@@ -363,7 +363,7 @@ def do_stack_abandon(hc, args):
             try:
                 with open(args.output_file, "w") as f:
                     f.write(result)
-            except IOError as err:
+            except OSError as err:
                 print(result)
                 raise exc.CommandError(str(err))
         else:
diff --git a/heatclient/v1/stacks.py b/heatclient/v1/stacks.py
index a303e63e..329b81f2 100644
--- a/heatclient/v1/stacks.py
+++ b/heatclient/v1/stacks.py
@@ -91,7 +91,7 @@ class Stack(base.Resource):
 
     @property
     def identifier(self):
-        return '%s/%s' % (self.stack_name, self.id)
+        return '{}/{}'.format(self.stack_name, self.id)
 
 
 class StackChildManager(base.BaseManager):
@@ -245,8 +245,8 @@ class StackManager(StackChildManager):
 
     def snapshot_show(self, stack_id, snapshot_id):
         stack_identifier = self._resolve_stack_id(stack_id)
-        resp = self.client.get('/stacks/%s/snapshots/%s' % (stack_identifier,
-                                                            snapshot_id))
+        resp = self.client.get('/stacks/{}/snapshots/{}'.format(
+            stack_identifier, snapshot_id))
         body = utils.get_response_body(resp)
         return body
 
@@ -278,10 +278,10 @@ class StackManager(StackChildManager):
 
     def output_show(self, stack_id, output_key):
         stack_identifier = self._resolve_stack_id(stack_id)
-        resp = self.client.get('/stacks/%(id)s/outputs/%(key)s' % {
-            'id': stack_identifier,
-            'key': output_key
-        })
+        resp = self.client.get('/stacks/{id}/outputs/{key}'.format(
+            id=stack_identifier,
+            key=output_key
+        ))
         body = utils.get_response_body(resp)
         return body
 
diff --git a/releasenotes/source/conf.py b/releasenotes/source/conf.py
index e88c5933..cdd86de3 100644
--- a/releasenotes/source/conf.py
+++ b/releasenotes/source/conf.py
@@ -1,4 +1,3 @@
-# -*- coding: utf-8 -*-
 #   Licensed under the Apache License, Version 2.0 (the "License"); you may
 #   not use this file except in compliance with the License. You may obtain
 #   a copy of the License at