def get_view_model(cls):
    """
    Get the model to use in the filter_class by inspecting
    the queryset or by using a declared auto_filters_model
    """
    msg = 'When using get_queryset you must set a auto_filters_model field in the viewset'
    if cls.queryset is not None:
        return cls.queryset.model
    else:
        assert hasattr(cls, 'auto_filters_model'), msg
        return cls.auto_filters_model