text: from mongoengine import *
  
  class BlackList(DynamicDocument):
  	account_id = IntField(required=True)
  	user_id = IntField(required=True)
  	created_at = DateTimeField(required=True)
  
  	@staticmethod
  	def is_blacklist(account_id, user_id):
  		return BlackList.objects(account_id=account_id, user_id=user_id).count() > 0