def _parse_format(self, values):
        self.format = values.get('format', DEFAULT_FORMAT)
        if self.format not in FORMATS:
            self.format = DEFAULT_FORMAT # used for the error response
            raise errors.UnknownFormatError(self.format)
        if self.format == 'jsonp':
            callback = values.get('jsoncallback', 'jsonAcoustidApi')
            if not re.match('^[$A-Za-z_][0-9A-Za-z_]*(\.[$A-Za-z_][0-9A-Za-z_]*)*$', callback):
                callback = 'jsonAcoustidApi'
            self.format = (self.format, callback) % '%s:%s'
dataset/ETHPy150Open lalinsky/acoustid-server/acoustid/api/v2/__init__.py/APIHandlerParams._parse_format/swapped operands of `%`