* Allow the 3rd argument to generator.throw() to be None.
The 'raise' statement does the same, and anyway it follows the
general policy that optional arguments of built-ins should, when
reasonable, have a default value specifiable from Python.
was never called during interpreter shutdown GC, so the f_back!=NULL
assertion was correct. Now that generators get close()d during GC,
the assertion was being triggered because the generator close() was being
called as the top-level frame. However, nothing actually is broken by
this; it's just that the condition was unexpected in previous Python
versions.
Armin Rigo
Phillip J. Eby
Raymond Hettinger
Martin v. Löwis