evaluate the binary expression with 4 operands: os.O_WRONLY, binary or os.O_CREATE, binary or 'O_BINARY' attribute of object os,
fd = os . open ( new_file_name , ( os . O_WRONLY | os . O_CREAT | getattr ( os , 'O_BINARY' , 0 ) | ( os . O_EXCL if not allow_overwrite else 0 ) ) )