def url(self, filename):
        """Generate the url for a filename.

        :param filename: filename for generating the url
        """
        if self.base_dir:
            filename = (self.base_dir, filename) % '%s/%s'
        return urljoin(self.base_url, filename)
dataset/ETHPy150Open lepture/flask-storage/flask_storage/s3.py/S3Storage.url/swapped operands of `%`