<SYSTEM_TASK:>
Solve the following problem using Python, implementing the functions described below, one line at a time
<END_TASK>
<USER_TASK:>
Description:
 def has_request(self, request):
 """Check if the given request already exists in the queue. Args: request (:class:`nyawc.http.Request`):
 The request to check. Returns: bool: True if already exists, False otherwise. """


        queue_item = QueueItem(request, Response(request.url))
        key = queue_item.get_hash()

        for status in QueueItem.STATUSES:
            if key in self.__get_var("items_" + status).keys():
                return True

        return False