def pack_content(self, filename, content):
        enc_filename = self.base64encode(filename) or '-'
        enc_content = (content or '').encode('base64')
        result = (enc_filename, enc_content) % '%s %s'
        return result
dataset/ETHPy150Open formencode/formencode/formencode/validators.py/FileUploadKeeper.pack_content/swapped operands of `%`