code: def list_files(self, offset=None, limit=None, api=None):
          
          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'
          )
docs: List files in a folder
          :param api: Api instance
          :param offset: Pagination offset
          :param limit: Pagination limit
          :return: List of files