def queryset(self, request, queryset):
    content_types = self.value()
    if (not content_types):
        return queryset
    return queryset.filter(version__content_type__in=content_types.split(','))
def queryset(self, request, queryset):
    content_types = self.value()
    if (not content_types):
        return queryset
    return queryset.filter(version__content_type__in=content_types.split(','))