code: def _get_receivers(self, sender):
          ''' filter only receiver functions which correspond to the provided sender '''
          key = _make_id(sender)
          receivers = []
          for (receiver_key, sender_key), receiver in self.receivers.items():
              if sender_key == key:
                  receivers.append(receiver)
          return receiverf _get_receivers(self, sender):
          ''' filter only receiver functions which correspond to the provided sender '''
          key = _make_id(sender)
          receivers = []
          for (receiver_key, sender_key), receiver in self.receivers.items():
              if sender_key == key:
                  receivers.append(receiver)
          return receivers
docs: filter only receiver functions which correspond to the provided sender