def init_app(self, app, **kwargs):
        """
        Allow to lazy register the API on a Flask application::

        >>> app = Flask(__name__)
        >>> api = Api()
        >>> api.init_app(app)

        :param flask.Flask app: the Flask application object
        :param str title: The API title (used in Swagger documentation)
        :param str description: The API description (used in Swagger documentation)
        :param str terms_url: The API terms page URL (used in Swagger documentation)
        :param str contact: A contact email for the API (used in Swagger documentation)
        :param str license: The license associated to the API (used in Swagger documentation)
        :param str license_url: The license page URL (used in Swagger documentation)
        :param url_scheme: If set to a string (e.g. http, https), then the specs_url and base_url will explicitly use
            this scheme regardless of how the application is deployed. This is necessary for some deployments behind a
            reverse proxy.
        """