diff --git a/kallithea/lib/auth.py b/kallithea/lib/auth.py
--- a/kallithea/lib/auth.py
+++ b/kallithea/lib/auth.py
@@ -24,26 +24,24 @@ Original author and date, and relevant c
 :copyright: (c) 2013 RhodeCode GmbH, and others.
 :license: GPLv3, see LICENSE.md for more details.
 """
-import collections
 import hashlib
 import itertools
 import logging
 import os
-import traceback
 
 import ipaddr
 from decorator import decorator
 from sqlalchemy.orm import joinedload
 from sqlalchemy.orm.exc import ObjectDeletedError
-from tg import request, session
+from tg import request
 from tg.i18n import ugettext as _
-from webob.exc import HTTPBadRequest, HTTPForbidden, HTTPFound, HTTPMethodNotAllowed
+from webob.exc import HTTPForbidden, HTTPFound
 
 from kallithea import __platform__, is_unix, is_windows
 from kallithea.config.routing import url
 from kallithea.lib.caching_query import FromCache
 from kallithea.lib.utils import conditional_cache, get_repo_group_slug, get_repo_slug, get_user_group_slug
-from kallithea.lib.utils2 import aslist, safe_str, safe_unicode
+from kallithea.lib.utils2 import safe_str, safe_unicode
 from kallithea.lib.vcs.utils.lazy import LazyProperty
 from kallithea.model.db import (
     Permission, RepoGroup, Repository, User, UserApiKeys, UserGroup, UserGroupMember, UserGroupRepoGroupToPerm, UserGroupRepoToPerm, UserGroupToPerm, UserGroupUserGroupToPerm, UserIpMap, UserToPerm)