code: def append(self, key, value, expire=0, noreply=None):
          
          if noreply is None:
              noreply = self.default_noreply
          return self._store_cmd(b'append', {key: value}, expire, noreply)[key]
docs: The memcached "append" command.
  
          Args:
            key: str, see class docs for details.
            value: str, see class docs for details.
            expire: optional int, number of seconds until the item is expired
                    from the cache, or zero for no expiry (the default).
            noreply: optional bool, True to not wait for the reply (defaults to
                     self.default_noreply).
  
          Returns:
            True.