oauth2.py is a script that can be used as a standalone utility for
generating and authorizing OAuth tokens, and for generating OAuth2
authentication strings from OAuth tokens.

This can be used with Mutt to allow oauth2 logins to Gmail, although
in newer version of Mutt (2.0+) an alternative written using Python 3
is available in ${PREFIX}/share/examples/mutt/mutt_oauth2.py.