code: def get_subscription_by_channel_id_and_endpoint_id(
              self, channel_id, endpoint_id):
          
          subscriptions = self.search_subscriptions(
              channel_id=channel_id, endpoint_id=endpoint_id)
  
          try:
              return subscriptions[0]
          except IndexError:
              raise DataFailureException(url, 404, "No subscription found")
docs: Search for subscription by a given channel and endpoint