Fix D401 PEP257 violation and enable H403

Currently tox ignores D401 and H403:
401: First line should be in imperative mood.
403: multi line docstrings should end on a new line

This change makes keystonemiddleware docstrings compliant with D401.
H403 is already passing, so this commit also enables it.

Change-Id: I9471721220c99f9c4ed055840ed626bb7750eb3f

keystonemiddleware/audit.py

@@ -444,7 +444,7 @@ class AuditMiddleware(object):
 
 
 def filter_factory(global_conf, **local_conf):
-    """Returns a WSGI filter app for use with paste.deploy."""
+    """Return a WSGI filter app for use with paste.deploy."""
     conf = global_conf.copy()
     conf.update(local_conf)
 

keystonemiddleware/auth_token/__init__.py

@@ -915,7 +915,7 @@ class AuthProtocol(BaseAuthProtocol):
             raise ksm_exceptions.InvalidToken(msg)
 
     def _cms_verify(self, data, inform=cms.PKI_ASN1_FORM):
-        """Verifies the signature of the provided data's IAW CMS syntax.
+        """Verify the signature of the provided data's IAW CMS syntax.
 
         If either of the certificate files might be missing, fetch them and
         retry.
@@ -1100,7 +1100,7 @@ class AuthProtocol(BaseAuthProtocol):
 
 
 def filter_factory(global_conf, **local_conf):
-    """Returns a WSGI filter app for use with paste.deploy."""
+    """Return a WSGI filter app for use with paste.deploy."""
     conf = global_conf.copy()
     conf.update(local_conf)
 

keystonemiddleware/auth_token/_memcache_crypt.py

@@ -88,7 +88,7 @@ if sys.version_info >= (3, 3):
     constant_time_compare = hmac.compare_digest
 else:
     def constant_time_compare(first, second):
-        """Returns True if both string inputs are equal, otherwise False.
+        """Return True if both string inputs are equal, otherwise False.
 
         This function should take a constant amount of time regardless of
         how many characters in the strings match.
@@ -107,7 +107,7 @@ else:
 
 
 def derive_keys(token, secret, strategy):
-    """Derives keys for MAC and ENCRYPTION from the user-provided secret.
+    """Derive keys for MAC and ENCRYPTION from the user-provided secret.
 
     The resulting keys should be passed to the protect and unprotect functions.
 

keystonemiddleware/auth_token/_user_plugin.py

@@ -95,7 +95,7 @@ class _TokenData(object):
 
     @property
     def trust_id(self):
-        """Returns the trust id associated with the authentication request..
+        """Return the trust id associated with the authentication request..
 
         :rtype: str
         """

keystonemiddleware/ec2_token.py

@@ -206,7 +206,7 @@ class EC2Token(object):
 
 
 def filter_factory(global_conf, **local_conf):
-    """Returns a WSGI filter app for use with paste.deploy."""
+    """Return a WSGI filter app for use with paste.deploy."""
     conf = global_conf.copy()
     conf.update(local_conf)
 

keystonemiddleware/s3_token.py

@@ -261,7 +261,7 @@ class S3Token(object):
 
 
 def filter_factory(global_conf, **local_conf):
-    """Returns a WSGI filter app for use with paste.deploy."""
+    """Return a WSGI filter app for use with paste.deploy."""
     conf = global_conf.copy()
     conf.update(local_conf)
 

tox.ini

@@ -47,9 +47,7 @@ commands = oslo_debug_helper {posargs}
 # D209: Multi-line docstring closing quotes should be on a separate line
 # D301: Use r""" if any backslashes in a docstring
 # D400: First line should end with a period
-# D401: First line should be in imperative mood
-# H403: multi line docstrings should end on a new line
-ignore = D100,D101,D102,D103,D104,D105,D200,D202,D209,D301,D204,D400,D401,H403
+ignore = D100,D101,D102,D103,D104,D105,D200,D202,D209,D301,D204,D400
 show-source = True
 exclude = .venv,.tox,dist,doc,*egg,build,*openstack/common*