I would like to give some feedback about ...

From: http://www.checkio.org/mission/median/solve/

HTTP_USER_AGENT:

Mozilla/5.0 (Windows NT 6.1; WOW64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/43.0.2357.134 Safari/537.36

I keep getting an error when [1 2 3 4 5] is passed, saying object NoneType has no method len() and is not iterable.