def _req_files_move(self, pid, fids):
        """
        Move files or directories
        :param str pid: destination directory id
        :param list fids: a list of ids of files or directories to be moved
        """
        url = self.web_api_url + '/move'
        data = {}
        data['pid'] = pid
        for i, fid in enumerate(fids):
            data['fid[%d]' % i] = fid
        req = Request(method='POST', url=url, data=data)
        res = self.http.send(req)
        if res.state:
            return True
        else:
            raise RequestFailure('Failed to access files API.')