I understand how bool works. I think you're still not understanding my question. 

I want to know, **for this function**, **for this algorithm**, is this *correct* behavior in this instance? If `t_area.is_nonpositive` gives `None`, is it correct for `_right` to return `False` (as opposed to returning `None`, or raising an exception, or some other behavior)? 

Maybe @smichr can comment too.