code: def append(self, frame_p):
          
          return lib.zmsg_append(self._as_parameter_, byref(zframe_p.from_param(frame_p)))
docs: Add frame to the end of the message, i.e. after all other frames.
  Message takes ownership of frame, will destroy it when message is sent.
  Returns 0 on success. Deprecates zmsg_add, which did not nullify the
  caller's frame reference.