Would __iadd__ and __isub__ be added to collections.abc.MutableMapping?

This would be consistent with other infix operations on mutable ABCs, but could potentially break backwards compatibility for anyone who has defined a MutableMapping subclass that implements __add__ but not __iadd__.
On Sat, Mar 9, 2019 at 8:55 AM Steven D'Aprano <steve@pearwood.info> wrote:
Thanks to everyone who has contributed to the discussion, I have been
reading all the comments even if I haven't responded.

I'm currently working on an update to the PEP which will, I hope,
improve some of the failings of the current draft.

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