Issue with current documentation:

The interface for the __array_finalize__ method in the ndarray class for numpy v1.22.0 has no arguments:

However, the documentation for subclassing an ndarray states that __array_finalize__ has one argument called obj.

I have code that subclasses ndarray following the documentation (so it takes the argument called obj), and it appears to work with numpy v1.22.0; however, it doesn't pass type checking with mypy due to it having a different type signature than the superclass.

Note that subclasses of ndarray in the interface (e.g., recarray) use the single argument in the __array_finalize__ method.

Which is correct? Or is something more complicated going on under the hood that makes them both correct?

I checked the devdocs and this issue is present in them as well.

Idea or request for content:

Fix the ndarray interface to have one argument or add a disclaimer to the subclassing documentation if something more complicated is going on under the hood.