hgdemandimport: add collections.abc to the ignore list because Python 3.13 rc3 It worked in Python 3.13 rc2, but something changed for rc3. Now, when i18n.py imports typing and it touches collections.abc.Hashable , we get: ValueError: module object for collections.abc substituted in sys.modules during a lazy load This seems to be a general problem, released in the final Python 3.13 . I have not analyzed the problem in details. We *could* work around the problem by disabling demand import of typing. But that would effectively disable demand import of collections.abc too. Instead, just disable demand import for collections.abc .