Antoine Pitrou <pitrou@free.fr> added the comment: The reason tp_del has remained undocumented is that it's now obsolete. You should use tp_finalize instead: https://docs.python.org/3/c-api/typeobj.html#c.PyTypeObject.tp_finalize tp_finalize is roughly the C equivalent of __del__ (tp_del was something else, despite the name). ---------- versions: +Python 3.7, Python 3.8 _______________________________________ Python tracker <report@bugs.python.org> <https://bugs.python.org/issue4934> _______________________________________