Parenthesize Py<type>_Check() in ifs In C, if expressions should be parenthesized. PyLong_Check, PyUnicode_Check etc. happened to expand to a parenthesized expression before, but that's not API to rely on. Since Python 3.9.0a4 it needs to be parenthesized explicitly. Fixes https://gitlab.gnome.org/GNOME/libxml2/issues/149