human
Here's a good function header given the following:
I wrote the below code

    def shift(n):
        return (('    <<    (%d    *    PyLong_SHIFT    <    8    *    sizeof(%s)    ?    %d    *    PyLong_SHIFT    :    0)' % (n, join_type, n)) if n else '')
    return ('(%s)' % '    |    '.join((('(((%s)%s[%d])%s)' % (join_type, digits_ptr, i, shift(i))) for i in range((count - 1), (-1), (-1)))))

What's a good function header?
assistant
#Here's a good function header.

def _pylong_join(count, digits_ptr='digits', join_type='unsigned    long'):