[issue42379] Optional List Args Persist Across Objects

[Steven D'Aprano]

Steven D'Aprano <steve+python at pearwood.info> added the comment:

Hi Rose, this is a FAQ:

https://docs.python.org/3/faq/programming.html#why-are-default-values-shared-between-objects

although it's also a feature that does cause beginners some trouble, see for example my comment here for more information:

https://bugs.python.org/msg361451

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nosy: +steven.daprano

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