Python Mechanize can no longer log into Amazon.com

[timur-tabi]

Starting a couple months ago, my Python Mechanize program stopped
being able to log into Amazon.com. The web site responds with
"Invalid username or password". Logging in via a web browser works
fine. Even downloading the HTML login form, opening it in a web
browser, and logging in that way also works. But for some reason,
Mechanize just can't do it.

Apparently, the Perl version of Mechanize has the same problem:
http://stackoverflow.com/questions/37409455/mechanize-perl-amazon-login-via-forms-unsuccessful

My script is here: https://github.com/timur-tabi/amazon-vine