diff --git a/aodhclient/shell.py b/aodhclient/shell.py
index 0307657..87ae7a6 100644
--- a/aodhclient/shell.py
+++ b/aodhclient/shell.py
@@ -59,7 +59,7 @@ class AodhShell(app.App):
             version=__version__,
             command_manager=AodhCommandManager('aodhclient'),
             deferred_help=True,
-            )
+        )
 
         self._client = None
 
diff --git a/aodhclient/tests/unit/test_alarm_cli.py b/aodhclient/tests/unit/test_alarm_cli.py
index 0745c84..04c7f55 100644
--- a/aodhclient/tests/unit/test_alarm_cli.py
+++ b/aodhclient/tests/unit/test_alarm_cli.py
@@ -42,7 +42,7 @@ class CliAlarmCreateTest(testtools.TestCase):
             '--aggregation-method', 'last',
             '--resource-type', 'generic',
             '--threshold', '80'
-            ])
+        ])
         self.cli_alarm_create._validate_args(test_parsed_args)
         mock_arg.assert_called_once_with(
             'gnocchi_resources_threshold requires --metric, '
@@ -58,7 +58,7 @@ class CliAlarmCreateTest(testtools.TestCase):
             '--name', 'threshold_test',
             '--type', 'threshold',
             '--threshold', '80'
-            ])
+        ])
         self.cli_alarm_create._validate_args(test_parsed_args)
         mock_arg.assert_called_once_with(
             'Threshold alarm requires -m/--meter-name and '
@@ -73,7 +73,7 @@ class CliAlarmCreateTest(testtools.TestCase):
         test_parsed_args = parser.parse_args([
             '--name', 'composite_test',
             '--type', 'composite'
-            ])
+        ])
         self.cli_alarm_create._validate_args(test_parsed_args)
         mock_arg.assert_called_once_with(
             'Composite alarm requires --composite-rule parameter')
@@ -90,7 +90,7 @@ class CliAlarmCreateTest(testtools.TestCase):
             '--aggregation-method', 'last',
             '--resource-type', 'generic',
             '--threshold', '80'
-            ])
+        ])
         self.cli_alarm_create._validate_args(test_parsed_args)
         mock_arg.assert_called_once_with(
             'gnocchi_aggregation_by_resources_threshold requires '
@@ -107,7 +107,7 @@ class CliAlarmCreateTest(testtools.TestCase):
             '--type', 'gnocchi_aggregation_by_metrics_threshold',
             '--resource-type', 'generic',
             '--threshold', '80'
-            ])
+        ])
         self.cli_alarm_create._validate_args(test_parsed_args)
         mock_arg.assert_called_once_with(
             'gnocchi_aggregation_by_metrics_threshold requires '
@@ -145,7 +145,7 @@ class CliAlarmCreateTest(testtools.TestCase):
             '--stack-id', '0809ab348-8b0e-451c-be28-abe250ae9c1c',
             '--pool-id', '79832aabf-343ba-be28-abe250ae9c1c',
             '--autoscaling-group-id', 'abe250ae9c1c-79832aabf-343ba-be28'
-            ])
+        ])
 
         # Output for the test
         alarm = {
@@ -217,7 +217,7 @@ class CliAlarmCreateTest(testtools.TestCase):
             },
             'composite_rule': None,
             'type': 'event'
-            }
+        }
         alarm_rep = self.cli_alarm_create._alarm_from_args(test_parsed_args)
         self.assertEqual(alarm, alarm_rep)
 
diff --git a/aodhclient/utils.py b/aodhclient/utils.py
index 8d2fd55..4b6577f 100644
--- a/aodhclient/utils.py
+++ b/aodhclient/utils.py
@@ -25,7 +25,7 @@ operator = pp.Regex(u"|".join(binary_operator))
 null = pp.Regex("None|none|null").setParseAction(pp.replaceWith(None))
 boolean = "False|True|false|true"
 boolean = pp.Regex(boolean).setParseAction(lambda t: t[0].lower() == "true")
-hex_string = lambda n: pp.Word(pp.hexnums, exact=n)
+hex_string = lambda n: pp.Word(pp.hexnums, exact=n)  # noqa: E731
 uuid = pp.Combine(hex_string(8) + ("-" + hex_string(4)) * 3 +
                   "-" + hex_string(12))
 number = r"[+-]?\d+(:?\.\d*)?(:?[eE][+-]?\d+)?"
diff --git a/tox.ini b/tox.ini
index 38f661f..1e7b5a6 100644
--- a/tox.ini
+++ b/tox.ini
@@ -21,7 +21,7 @@ deps =
 commands = pifpaf run aodh -- stestr run --slowest {posargs}
 
 [testenv:pep8]
-deps = hacking<0.13,>=0.12
+deps = hacking<3.1.0,>=3.0
 commands = flake8
 
 [testenv:venv]
@@ -55,4 +55,7 @@ commands = pifpaf --debug run aodh -- oslo_debug_helper {posargs}
 
 [flake8]
 show-source = True
+# W503 line break before binary operator
+# W504 line break after binary operator
+ignore = W503,W504
 exclude=.venv,.git,.tox,dist,doc,*egg,build