diff --git a/src/caosdb/connection/authentication/external_credentials_provider.py b/src/caosdb/connection/authentication/external_credentials_provider.py
index bebe43fedf215dfc2b744fbc0c96d7e9d50ba3e5..1cf4cefc90de2a0281528eb83c1efe55eda4f345 100644
--- a/src/caosdb/connection/authentication/external_credentials_provider.py
+++ b/src/caosdb/connection/authentication/external_credentials_provider.py
@@ -21,8 +21,7 @@
 #
 # ** end header
 #
-"""external_credentials_provider.
-"""
+"""external_credentials_provider."""
 from __future__ import absolute_import, unicode_literals
 from abc import ABCMeta
 import logging
diff --git a/src/caosdb/connection/authentication/interface.py b/src/caosdb/connection/authentication/interface.py
index 8be18b57352a1f89bf139a5b569970ff483472d1..745517a2ab1b884a1fad5e0627ffd9de26853ed6 100644
--- a/src/caosdb/connection/authentication/interface.py
+++ b/src/caosdb/connection/authentication/interface.py
@@ -126,7 +126,7 @@ class AbstractAuthenticator(ABC):
 
     def on_request(self, method, path, headers, **kwargs):
         # pylint: disable=unused-argument
-        """on_request
+        """on_request.
 
         A call-back which is to be called by the connection before each
         request. This method set the auth cookie for that request.
@@ -150,7 +150,7 @@ class AbstractAuthenticator(ABC):
 
 
 class CredentialsAuthenticator(AbstractAuthenticator):
-    """CredentialsAuthenticator
+    """CredentialsAuthenticator.
 
     Subclass of AbstractAuthenticator which provides authentication via
     credentials (username/password). This class always needs a
diff --git a/src/caosdb/connection/interface.py b/src/caosdb/connection/interface.py
index 58acf60985c9e318d1642301660bf7de8e984715..a6f739171597a848356321578f4a4065a2e94006 100644
--- a/src/caosdb/connection/interface.py
+++ b/src/caosdb/connection/interface.py
@@ -67,8 +67,8 @@ class CaosDBHTTPResponse(ABC):
     def close(self):
         """close.
 
-        Close this response. Depending on the implementation this might also
-        close underlying streams, sockets etc.
+        Close this response. Depending on the implementation this might
+        also close underlying streams, sockets etc.
         """
 
 
diff --git a/src/caosdb/connection/utils.py b/src/caosdb/connection/utils.py
index c1245a088e868077a817f9a7877a1ae51bf9fb9f..8c1518c1ba66b45c69d5b9fa0d137f0df633cd0c 100644
--- a/src/caosdb/connection/utils.py
+++ b/src/caosdb/connection/utils.py
@@ -164,8 +164,10 @@ def check_python_ssl_version(hexversion):
             "\nPython 3 version is smaller than 3.2. It is not does not fully support SSL encryption. Please update your Python to 2.7.9 or greater, or 3.2 or greater."
         )
 
+
 _PATTERN = re.compile(r"^SessionToken=([^;]*);.*$")
 
+
 def unquote(string):
     """unquote.
 
@@ -177,6 +179,7 @@ def unquote(string):
         return bts.decode("utf-8")
     return bts
 
+
 def parse_auth_token(cookie):
     """parse_auth_token.
 
@@ -197,6 +200,7 @@ def parse_auth_token(cookie):
         auth_token = unquote(_PATTERN.split(cookie)[1])
     return auth_token
 
+
 def auth_token_to_cookie(auth_token):
     """auth_token_to_cookie.
 
diff --git a/unittests/test_authentication_keyring.py b/unittests/test_authentication_keyring.py
index 1105b9d29604e7809c1f6ab6d6a6d027c5115025..715514498b406478a3bddcc64c7794316f64368e 100644
--- a/unittests/test_authentication_keyring.py
+++ b/unittests/test_authentication_keyring.py
@@ -21,7 +21,7 @@
 #
 # ** end header
 #
-"""test_authentication_keyring
+"""test_authentication_keyring.
 
 Tests for the caosdb.connection.authentication.keyring module.
 """
diff --git a/unittests/test_authentication_pass.py b/unittests/test_authentication_pass.py
index e5e4870c890a6a19effe672a3fde127cb4ea1fd7..45bda08a46bcc95aa73e5609f053f3ac178901dc 100644
--- a/unittests/test_authentication_pass.py
+++ b/unittests/test_authentication_pass.py
@@ -21,7 +21,7 @@
 #
 # ** end header
 #
-"""test_authentication_pass
+"""test_authentication_pass.
 
 Tests for the caosdb.connection.authentication.pass module.
 """
diff --git a/unittests/test_connection_utils.py b/unittests/test_connection_utils.py
index 4af6319986c5f16be7e2a8bfeab6d2e92a3eb5a3..c21b453e3a7588f30d86be8d2ed39bb4d7a1d31e 100644
--- a/unittests/test_connection_utils.py
+++ b/unittests/test_connection_utils.py
@@ -21,7 +21,7 @@
 #
 # ** end header
 #
-"""Test caosdb.connection.utils"""
+"""Test caosdb.connection.utils."""
 # pylint: disable=missing-docstring
 from __future__ import unicode_literals, print_function
 from pytest import raises
@@ -47,5 +47,6 @@ def setup_module():
 def test_parse_auth_token():
     assert parse_auth_token("SessionToken=%5Bblablabla%5D; expires=bla; ...") == "[blablabla]"
 
+
 def test_auth_token_to_cookie():
     assert auth_token_to_cookie("[blablabla]") == "SessionToken=%5Bblablabla%5D;"