diff --git a/homeassistant/helpers/config_validation.py b/homeassistant/helpers/config_validation.py
index ef9781f480b..4b97409dd3d 100644
--- a/homeassistant/helpers/config_validation.py
+++ b/homeassistant/helpers/config_validation.py
@@ -637,7 +637,9 @@ def key_dependency(key, dependency):
 # Schemas
 class HASchema(vol.Schema):
     """Schema class that allows us to mark PREVENT_EXTRA errors as warnings."""
+
     def __call__(self, data):
+        """Override __call__ to mark PREVENT_EXTRA as warning."""
         try:
             return super().__call__(data)
         except vol.Invalid as orig_err:
@@ -646,6 +648,7 @@ class HASchema(vol.Schema):
 
             # orig_error is of type vol.MultipleInvalid (see super __call__)
             assert isinstance(orig_err, vol.MultipleInvalid)
+            # pylint: disable=no-member
             # If it fails with PREVENT_EXTRA, try with ALLOW_EXTRA
             self.extra = vol.ALLOW_EXTRA
             # In case it still fails the following will raise
@@ -676,7 +679,7 @@ class HASchema(vol.Schema):
             return validated
 
     def extend(self, schema, required=None, extra=None):
-        """Extend this schema and convert it to HASchema if necessary"""
+        """Extend this schema and convert it to HASchema if necessary."""
         ret = super().extend(schema, required=required, extra=extra)
         if extra is not None:
             return ret
diff --git a/tests/test_setup.py b/tests/test_setup.py
index 1a60943a72d..c6126bc4a3b 100644
--- a/tests/test_setup.py
+++ b/tests/test_setup.py
@@ -117,7 +117,8 @@ class TestSetup:
                     'invalid': 'extra',
                 }
             })
-            assert caplog.text.count('Your configuration contains extra keys') == 1
+            assert caplog.text.count('Your configuration contains '
+                                     'extra keys') == 1
 
         self.hass.data.pop(setup.DATA_SETUP)
         self.hass.config.components.remove('platform_conf')
@@ -133,7 +134,8 @@ class TestSetup:
                     'invalid': True
                 }
             })
-            assert caplog.text.count('Your configuration contains extra keys') == 2
+            assert caplog.text.count('Your configuration contains '
+                                     'extra keys') == 2
 
         self.hass.data.pop(setup.DATA_SETUP)
         self.hass.config.components.remove('platform_conf')
@@ -215,7 +217,8 @@ class TestSetup:
                     'invalid': 'extra',
                 }
             })
-            assert caplog.text.count('Your configuration contains extra keys') == 1
+            assert caplog.text.count('Your configuration contains '
+                                     'extra keys') == 1
 
         self.hass.data.pop(setup.DATA_SETUP)
         self.hass.config.components.remove('platform_conf')
@@ -266,7 +269,8 @@ class TestSetup:
                     'invalid': 'extra',
                 }
             })
-            assert caplog.text.count('Your configuration contains extra keys') == 1
+            assert caplog.text.count('Your configuration contains '
+                                     'extra keys') == 1
 
         self.hass.data.pop(setup.DATA_SETUP)
         self.hass.config.components.remove('platform_conf')