def define_example_values(self, http_method, route, values, update=False):
        """Define example values for a given request.

        By default, example values are determined from the example properties
        in the schema. But if you want to change the example used in the
        documentation for a specific route, and this method lets you do that.

        :param str http_method: An HTTP method, like "get".
        :param str route: The route to match.
        :param dict values: A dictionary of parameters for the example request.
        :param bool update: If True, the values will be merged into the default
            example values for the request. If False, the values will replace
            the default example values.
        """
        self.defined_example_values[(http_method.lower(), route)] = {
            'update': update,
            'values': values
        }