I'm the leader of the pandas-stubs project. In pandas, users can extend the library by creating their own accessor via `@pd.api.extensions.register_dataframe_accessor` (see https://pandas.pydata.org/docs/reference/api/pandas.api.extensions.register_...). So for a `DataFrame`, if you do `@pd.api.extensions.register_dataframe_accessor("xyz")`, you now have `DataFrame.xyz` returning the class you annotated. Now suppose you want to create a stub for your new accessor, that would extend the existing pandas-stubs. AFAIK, there isn't a way to do something like this in a stub: ``` from pandas import DataFrame @typing.extend class DataFrame: def xyz(self) -> MyXyzClass: ... ``` The idea here is that there is a class (in this case, `DataFrame`) that already has stubs, and you want to add a method to it. Has this idea been discussed anywhere?