code: def accept(self):
          
          if self._can_settle_message():
              self._response = errors.MessageAccepted()
              self._settler(self._response)
              self.state = constants.MessageState.ReceivedSettled
              return True
          return False
docs: Send a response disposition to the service to indicate that
          a received message has been accepted. If the client is running in PeekLock
          mode, the service will wait on this disposition. Otherwise it will
          be ignored. Returns `True` is message was accepted, or `False` if the message
          was already settled.
  
          :rtype: bool
          :raises: TypeError if the message is being sent rather than received.