fix imports and styling

src/caosdb/common/administration.py

@@ -32,7 +32,10 @@ from caosdb.common.utils import xml2str
 from caosdb.connection.connection import get_connection
 from caosdb.exceptions import (HTTPClientError,
                                HTTPForbiddenError,
-                               HTTPResourceNotFoundError)
+                               HTTPResourceNotFoundError,
+                               EntityDoesNotExistError,
+                               ServerConfigurationException,
+                               )
 
 
 def set_server_property(key, value):

src/caosdb/connection/connection.py

@@ -619,4 +619,3 @@ class _Connection(object):  # pylint: disable=useless-object-inheritance
         Shortcut for: get_connection()._authenticator._credentials_provider.username
         """
         return self._authenticator._credentials_provider.username
-