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Solve the following problem using Python, implementing the functions described below, one line at a time
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Description:
 def setup_generic_relations(model_class):
 """ Set up GenericRelations for actionable models. """

    Action = apps.get_model('actstream', 'action')

    if Action is None:
        raise RegistrationError(
            'Unable get actstream.Action. Potential circular imports '
            'in initialisation. Try moving actstream app to come after the '
            'apps which have models to register in the INSTALLED_APPS setting.'
        )

    related_attr_name = 'related_query_name'
    related_attr_value = 'actions_with_%s' % label(model_class)

    relations = {}
    for field in ('actor', 'target', 'action_object'):
        attr = '%s_actions' % field
        attr_value = '%s_as_%s' % (related_attr_value, field)
        kwargs = {
            'content_type_field': '%s_content_type' % field,
            'object_id_field': '%s_object_id' % field,
            related_attr_name: attr_value
        }
        rel = GenericRelation('actstream.Action', **kwargs)
        rel.contribute_to_class(model_class, attr)
        relations[field] = rel

        # @@@ I'm not entirely sure why this works
        setattr(Action, attr_value, None)
    return relations