markovify's make_sentence_with_start() doesn't seem to work properly

[nezetimesthree]

heya @jsvine. i'm writing a quite simple code with markovify, and i keep running into couple of issues.

1. m_s_w_s doesn't see the sentences with words when they're clearly there, strict=False
2. for some reason, when my generated prompt is exactly two word-long, it gives me a KeyErrorL: ('wors_a', 'word_b)'). it works in some cases as it expected to work, though, but in my tests issues happen a lot more often. i can give you the code if you need it.