diff --git a/classquiz/helpers/hashcash.py b/classquiz/helpers/hashcash.py
index b589abc..06def31 100644
--- a/classquiz/helpers/hashcash.py
+++ b/classquiz/helpers/hashcash.py
@@ -81,10 +81,10 @@ def mint(resource, bits=20, now=None, ext="", saltchars=8, stamp_seconds=False):
     return challenge + _mint(challenge, bits)
 
 
-def _salt(l):
-    "Return a random string of length 'l'"
+def _salt(length):
+    "Return a random string of length 'length'"
     alphabet = ascii_letters + "+/="
-    return "".join([choice(alphabet) for _ in [None] * l])
+    return "".join([choice(alphabet) for _ in [None] * length])
 
 
 def _mint(challenge, bits):
diff --git a/classquiz/routers/quiz.py b/classquiz/routers/quiz.py
index 0253e35..1d3c48f 100644
--- a/classquiz/routers/quiz.py
+++ b/classquiz/routers/quiz.py
@@ -169,7 +169,7 @@ async def update_quiz(quiz_id: str, quiz_input: QuizInput, user: User = Depends(
         quiz_id = uuid.UUID(quiz_id)
     except ValueError:
         raise HTTPException(status_code=400, detail="badly formed quiz id")
-    ## Check Cover-Image
+    # Check Cover-Image
 
     print(quiz_input.cover_image)
     if quiz_input.cover_image == "":
diff --git a/classquiz/socket_server/__init__.py b/classquiz/socket_server/__init__.py
index 802a44a..a253f62 100644
--- a/classquiz/socket_server/__init__.py
+++ b/classquiz/socket_server/__init__.py
@@ -11,9 +11,9 @@ import socketio
 from cryptography.fernet import Fernet
 
 from classquiz.config import redis, settings
-from classquiz.db.models import PlayGame, QuizQuestionType, GameSession, GamePlayer, RangeQuizAnswer, QuizQuestion
+from classquiz.db.models import PlayGame, QuizQuestionType, GameSession, GamePlayer, QuizQuestion
 from pydantic import BaseModel, ValidationError, validator
-from datetime import timedelta, datetime
+from datetime import datetime
 
 sio = socketio.AsyncServer(async_mode="asgi", cors_allowed_origins=[])
 settings = settings()
diff --git a/classquiz/tests/__init__.py b/classquiz/tests/__init__.py
index ed7190b..0729c0d 100644
--- a/classquiz/tests/__init__.py
+++ b/classquiz/tests/__init__.py
@@ -57,7 +57,30 @@ example_quiz = {
 test_user_email = "sth@byom.de"
 test_user_password = "test"
 
-# mock_test_results = {'0': [{'username': 'Player 1', 'answer': 'Byte, Bit, KB, MB, GB, TB', 'right': False}, {'username': 'Player 2', 'answer': 'Byte, Bit, KB, MB, GB, TB', 'right': False}, {'username': 'Player 3', 'answer': 'Bit, Byte, KB, MB, GB, TB', 'right': True}], '1': [{'username': 'Player 3', 'answer': 'CPU', 'right': True}, {'username': 'Player 2', 'answer': 'CPU', 'right': True}, {'username': 'Player 1', 'answer': 'CPU', 'right': True}], '2': [{'username': 'Player 1', 'answer': 'Peripheriegeräte', 'right': True}, {'username': 'Player 2', 'answer': 'Speichergeräte', 'right': False}, {'username': 'Player 3', 'answer': 'Kommunikationsgeräte', 'right': False}], '3': [{'username': 'Player 1', 'answer': 'die Taktfrequenz der CPU', 'right': True}, {'username': 'Player 2', 'answer': 'die Taktfrequenz der CPU', 'right': True}, {'username': 'Player 3', 'answer': 'die Taktfrequenz der CPU', 'right': True}], '4': [{'username': 'Player 3', 'answer': 'Drucker', 'right': True}, {'username': 'Player 2', 'answer': 'Drucker', 'right': True}, {'username': 'Player 1', 'answer': 'Tabellenkalkulation', 'right': False}], '5': [{'username': 'Player 1', 'answer': 'CPU (Central Processing Unit)', 'right': False}, {'username': 'Player 2', 'answer': 'RAM (Random Access Memory)', 'right': True}, {'username': 'Player 3', 'answer': 'RAM (Random Access Memory)', 'right': True}], '6': [{'username': 'Player 3', 'answer': 'RAM', 'right': True}, {'username': 'Player 2', 'answer': 'ROM', 'right': False}, {'username': 'Player 1', 'answer': 'RAM', 'right': True}], '7': [{'username': 'Player 1', 'answer': '1 TB (Terabyte)', 'right': True}, {'username': 'Player 2', 'answer': '500 KB (Kilobyte)', 'right': False}, {'username': 'Player 3', 'answer': '500 TB (Terabyte)', 'right': False}], '8': [{'username': 'Player 3', 'answer': 'Tabellenkalkulationsprogramm', 'right': True}, {'username': 'Player 2', 'answer': 'Tabellenkalkulationsprogramm', 'right': True}, {'username': 'Player 1', 'answer': 'Linux', 'right': False}], '9': [{'username': 'Player 1', 'answer': 'Anwendungsprogramme', 'right': True}, {'username': 'Player 2', 'answer': 'Lernprogramme', 'right': False}, {'username': 'Player 3', 'answer': 'Anwendungsprogramme', 'right': True}]}
+# mock_test_results = {'0': [{'username': 'Player 1', 'answer': 'Byte, Bit, KB, MB, GB, TB', 'right': False},
+# {'username': 'Player 2', 'answer': 'Byte, Bit, KB, MB, GB, TB', 'right': False}, {'username': 'Player 3',
+# 'answer': 'Bit, Byte, KB, MB, GB, TB', 'right': True}], '1': [{'username': 'Player 3', 'answer': 'CPU',
+# 'right': True}, {'username': 'Player 2', 'answer': 'CPU', 'right': True}, {'username': 'Player 1',
+# 'answer': 'CPU', 'right': True}], '2': [{'username': 'Player 1', 'answer': 'Peripheriegeräte',
+# 'right': True}, {'username': 'Player 2', 'answer': 'Speichergeräte', 'right': False},
+# {'username': 'Player 3', 'answer': 'Kommunikationsgeräte', 'right': False}], '3': [{'username': 'Player 1',
+# 'answer': 'die Taktfrequenz der CPU', 'right': True}, {'username': 'Player 2',
+# 'answer': 'die Taktfrequenz der CPU', 'right': True}, {'username': 'Player 3',
+# 'answer': 'die Taktfrequenz der CPU', 'right': True}], '4': [{'username': 'Player 3', 'answer': 'Drucker',
+# 'right': True}, {'username': 'Player 2', 'answer': 'Drucker', 'right': True}, {'username': 'Player 1',
+# 'answer': 'Tabellenkalkulation', 'right': False}], '5': [{'username': 'Player 1',
+# 'answer':'CPU (Central Processing Unit)', 'right': False}, {'username': 'Player 2',
+# 'answer': 'RAM (Random Access Memory)', 'right': True}, {'username': 'Player 3',
+# 'answer': 'RAM (Random Access Memory)', 'right': True}], '6': [{'username': 'Player 3', 'answer': 'RAM',
+# 'right': True}, {'username': 'Player 2', 'answer': 'ROM', 'right': False}, {'username': 'Player 1',
+# 'answer': 'RAM', 'right': True}], '7': [{'username': 'Player 1', 'answer': '1 TB (Terabyte)',
+# 'right': True}, {'username': 'Player 2', 'answer': '500 KB (Kilobyte)', 'right': False},
+# {'username': 'Player 3', 'answer': '500 TB (Terabyte)', 'right': False}], '8': [{'username': 'Player 3',
+# 'answer': 'Tabellenkalkulationsprogramm', 'right': True}, {'username': 'Player 2',
+# 'answer': 'Tabellenkalkulationsprogramm', 'right': True}, {'username': 'Player 1', 'answer': 'Linux',
+# 'right': False}], '9': [{'username': 'Player 1', 'answer': 'Anwendungsprogramme', 'right': True},
+# {'username': 'Player 2', 'answer': 'Lernprogramme', 'right': False}, {'username': 'Player 3',
+# 'answer': 'Anwendungsprogramme', 'right': True}]}
 
 
 @pytest.fixture(scope="module")
diff --git a/migrations/env.py b/migrations/env.py
index 1c43a7a..8a1f2a8 100644
--- a/migrations/env.py
+++ b/migrations/env.py
@@ -6,8 +6,6 @@ from logging.config import fileConfig
 from classquiz.db.models import metadata
 from classquiz.config import settings
 from sqlalchemy import create_engine
-from sqlalchemy.ext.asyncio import async_engine_from_config
-import asyncio
 
 from alembic import context