• Cannot understand where the error coming from

 

I would like to give some feedback about ...

From: https://py.checkio.org/mission/between-markers-simplified/solve/

HTTP_USER_AGENT:

Mozilla/5.0 (Macintosh; Intel Mac OS X 10_15_7) AppleWebKit/537.36 (KHTML, like Gecko) Chrome/91.0.4472.77 Safari/537.36