I would like to give some feedback about ...

From: http://www.checkio.org/mission/right-to-left/solve/ def left_join(*args): x=args z=[] for palabra in x: z.append(palabra.replace("right","left")) print ','.join(map(str,z))

¿why not works?

HTTP_USER_AGENT:

Mozilla/5.0 (Windows NT 6.2; WOW64; rv:40.0) Gecko/20100101 Firefox/40.0