I would like to give some feedback about ...

From: http://www.checkio.org/mission/right-to-left/solve/

HTTP_USER_AGENT:

Mozilla/5.0 (Windows NT 6.1; WOW64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/40.0.2214.115 Safari/537.36

def left_join(phrases): for w in phrases: w.replace("right","left") m = phrases[0] a = len(phrases) j = 1 while j < a : m += ',' m += phrases[j] j += 1 return m

replace do not work