Ezio told me my previous comment was hard to understand.  For the record, what I meant was that if you have a statement like, "If *allow_nan* is ``True``, then ....  Otherwise, ...," then this can be read to mean that something like 1 for *allow_nan* would be covered by the otherwise clause (because otherwise means "or else").

Changing "If *allow_nan* is ``True``" to "equals ``True``" would be one way to address this while still stating the preferred value.  But as I told Ezio on IRC, I would be okay with whatever you come up with.