def lookups(self, request, model_admin):
    lookup_list = []
    for content_model in _cms_extension().versionables_by_content:
        if hasattr(content_model, 'polymorphic_ctype'):
            content_model = get_base_polymorphic_model(content_model)
        content_type = ContentType.objects.get_for_model(content_model)
        lookup_list_entry = (content_type.pk, content_type)
        if (lookup_list_entry not in lookup_list):
            lookup_list.append(lookup_list_entry)
    return lookup_list
def lookups(self, request, model_admin):
    lookup_list = []
    for content_model in _cms_extension().versionables_by_content:
        if hasattr(content_model, 'polymorphic_ctype'):
            content_model = get_base_polymorphic_model(content_model)
        content_type = ContentType.objects.get_for_model(content_model)
        lookup_list_entry = (content_type.pk, content_type)
        if (lookup_list_entry not in lookup_list):
            lookup_list.append(lookup_list_entry)
    return lookup_list