That wording isn't much better in my opinion.  If I'm sitting there looking at methods like str.isdigit(), str.isnumeric(), str.isascii(), and str.isidentifier(), seeing keyword.iskeyword() makes me think it's a method regardless of whether you label it a function or method.  Explicitly stating that "keyword" is actually the keyword module makes it much clearer. Or at least including the argument as well keyword.iskeyword(kw).

It really should be a string method though ;-)