def list_files(self, offset=None, limit=None, api=None):
        """List files in a folder
        :param api: Api instance
        :param offset: Pagination offset
        :param limit: Pagination limit
        :return: List of files
        """
        api = api or self._API

        if not self.is_folder():
            raise SbgError('{name} is not a folder'.format(name=self.name))

        url = self._URL['list_folder'].format(id=self.id)

        return super(File, self.__class__)._query(
            api=api, url=url, offset=offset, limit=limit, fields='_all'
        )