def _complete_url(self, url_part, registration_prefix):
parts = {<EOL>'<STR_LIT:b>': registration_prefix,<EOL>'<STR_LIT:a>': self.prefix,<EOL>'<STR_LIT:e>': url_part<EOL>}<EOL>return '<STR_LIT>'.join(parts[key] for key in self.url_part_order if parts[key])<EOL>
This method is used to defer the construction of the final url in
        the case that the Api is created with a Blueprint.

        :param url_part: The part of the url the endpoint is registered with
        :param registration_prefix: The part of the url contributed by the
            blueprint.  Generally speaking, BlueprintSetupState.url_prefix