In fact cannot be smaller than 1, not 0. So should be "<= 0", due if in a test you pass a 0º angle it won't enter to the first condition but give you a result anyway, but an angle can't be 0, this is a line, right?

a or b returns the minimum of a,b you can try it out

You're right that this is wrong but (a or b) still can be < 0 because it's a if a != 0 else b.

Um... no.

The construct if (a or b) < 0 will never be True, because (a or b) is parsed as a boolean clause ((a != 0) or (b != 0)) which can only return False (0) or True (1), which can never be < 0.

You meant to write if (a < 0) or (b < 0):.