I would like to give some feedback about your answer to test 27 of the Most Frequent Days.

Is the answer correct for test number 27? I find Friday and my research seems to confirm it. 2100 will start and end on a Friday, but you seem to accept Monday as an answer.

From: https://py.checkio.org/mission/the-most-frequent-weekdays/solve/

HTTP_USER_AGENT:

Mozilla/5.0 (X11; Ubuntu; Linux x86_64; rv:50.0) Gecko/20100101 Firefox/50.0