python / tinymail.Account.set_pass_func

[Shikhar <shikhar schmizz net>]

I would appreciate some guidance about how to make use of 
tinymail.Account.set_pass_func()

What would the (Python) signature of the function be?

Also, with regard to tinymail.Account.set_secure_auth_mech(), is 
'STARTTLS' a valid argument / what is the equivalent?

Thanks,

Shikhar