@staticmethod
def _make_obj(model, _clean=True, **kwargs):
    """ Make an instance of a model

        Args:
            model (:obj:`type`): type of model to instantiate
            _clean (:obj:`bool`): if :obj:`True`, clean the instance of :obj:`model`
            kwargs (:obj:`dict`, optional): arguments to constructor of :obj:`model`
        """
    obj = model(**kwargs)
    if _clean:
        err = obj.clean()
    if err is not None:
        raise ValueError('Unable to clean {}: {}'.format(model.__name__,
            str(err)))
    return obj
