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 after_request(response):
    response.headers.add('X-Test', 'This is only test.')
    response.headers.add('Access-Control-Allow-Origin', '*')  # TODO: set to real origin
    return response