Hello. In mnya problem with the solution of the problem: Locally, I have worked faithfully. But in your test system at the 3 best samples gives no true result.

From: https://checkio.org/mission/find-friends/

HTTP_USER_AGENT:

Mozilla/5.0 (Windows NT 6.1; WOW64) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/50.0.2661.102 Safari/537.36