def dump(self):
        """
        :return: 当前对象的序列化结果
        :rtype: dict
        """
        params = {
            'where': self._where,
        }
        if self._include:
            params['include'] = ','.join(self._include)
        if self._select:
            params['keys'] = ','.join(self._select)
        if self._include_acl is not None:
            params['returnACL'] = json.dumps(self._include_acl)
        if self._limit >= 0:
            params['limit'] = self._limit
        if self._skip > 0:
            params['skip'] = self._skip
        if self._order:
            params['order'] = ",".join(self._order)
        params.update(self._extra)
        return params
:return: 当前对象的序列化结果
        :rtype: dict