Warning for invalid part of speech

[mpkasa]

I spent a while tracing the UnboundedLocalError that occurs when you set pos to something invalid (in my case, to "adjective" instead of "adj"). I'd like to suggest a warning for invalid parts of speech.

(Thanks for this package! I'm using it to help me write an email to my uncle which can be typed entirely with one hand.)

[red pills]

@mpkasa Thanks for reporting the issue.We have fixed the issue in latest version 1.0.4. And you have earned special mention in our release notes ;)