> Looks like it can simply be done in Python, no tp_as_mapping needed. It's not that it isn't needed. You've just shown a way to add it using Python code.
But, more to the point: extending collections.abc.Mapping may or may not be possible in OP's case. Also, if you are doing this through inheritance, this seems really convoluted: why not just inherit from dict? -- less methods to implement, less stuff to import etc. -- https://mail.python.org/mailman/listinfo/python-list
