@classmethod
def _add_description_factory(cls, descr):
    """Factory method which populates the un-set class variables

        Returns:
          new dataloader class
        """
    for field in ['type', 'defined_as', 'args', 'output_schema', 'info',
        'dependencies', 'path', 'postprocessing']:
        setattr(cls, field, getattr(descr, field))
    return cls
