code: def watch(self, *keys):
          
          if self.explicit_transaction:
              raise RedisError("Cannot issue a WATCH after a MULTI")
          self.watching = True
          for key in keys:
              self._watched_keys[key] = deepcopy(self.mock_redis.redis.get(self.mock_redis._encode(key)))
docs: Put the pipeline into immediate execution mode.
          Does not actually watch any keys.