code: def __handle_known_solicited(self, msg):
          
          with self.__requests:
              try:
                  req = self.__requests[msg[M_CLIENTREF]]
              except KeyError:
                  return False
  
              if self.__handle_low_seq_resend(msg, req):
                  return True
  
              perform_cb = finish = False
              if msg[M_TYPE] not in _RSP_NO_REF:
                  self.__update_existing(msg, req)
                  # Finalise request if applicable (not marked as finished here so can perform callback first below)
                  if msg[M_TYPE] in _RSP_TYPE_FINISH:
                      finish = True
                      # Exception - DUPLICATED also should produce callback
                      perform_cb = (msg[M_TYPE] == E_DUPLICATED)
                  elif msg[M_TYPE] not in _RSP_TYPE_ONGOING:
                      perform_cb = True
              else:
                  logger.warning('Reference unexpected for request %s of type %s', msg[M_CLIENTREF],
                                 msg[M_TYPE])
  
          # outside lock to avoid deadlock if callbacks try to perform request-related functions
          if perform_cb:
              self.__perform_unsolicited_callbacks(msg)
  
          # mark request as finished
          if finish:
              req.success = msg[M_TYPE] in _RSP_TYPE_SUCCESS
              req.payload = msg[M_PAYLOAD]
              self.__clear_references(req)
              # Serialise completion of CRUD requests (together with CREATED, DELETED, etc. messages)
              if req.is_crud:
                  self.__crud_threadpool.submit(req._set)
              else:
                  req._set()
  
          return True
docs: returns True if message has been handled as a solicited response