Format code with black

This commit fixes the style issues introduced in 88a8cec according to the output
from black.

Details: https://deepsource.io/gh/mawoka-myblock/ClassQuiz/transform/0eaa4519-980e-466d-ac20-6de04a1f1c8b/

classquiz/socket_server/__init__.py

@@ -170,4 +170,4 @@ async def get_final_results(sid, _data):
             break
         else:
             results[str(i)] = json.loads(redis_res)
-    await sio.emit("final_results", results, room=session['game_pin'])
+    await sio.emit("final_results", results, room=session["game_pin"])