@classmethod
def _get_serializable_model(cls):
    """
        Returns a model with a valid _meta.local_fields (serializable).

        Basically, this means the original model, not a proxied model.

        (this is a workaround for a bug in django)
        """
    current_class = cls
    while current_class._meta.proxy:
        current_class = current_class._meta.proxy_for_model
    return current_class
