def save(self, filename=None):
        filename = Path(filename) if filename is not None else self.filename
        with filename.open("w") as f:
            f.write(self.yaml)
def export(self, request):
        serializer = ConditionExportSerializer(self.get_queryset(), many=True)
        xml = ConditionRenderer().render(serializer.data)
        return XMLResponse(xml, name='conditions')