BUG: Arugment nan_as_null is unused in __dataframe__ calls.

[ethandavidlee]

Pandas version checks

• I have checked that this issue has not already been reported.

• I have confirmed this bug exists on the latest version of pandas.

• I have confirmed this bug exists on the main branch of pandas.

Reproducible Example

Code review of frame.py (line 904).

Issue Description

The arugment nan_as_null is unused in dataframe calls (Line 904 in frame.py) and should be removed. A comment notes that "nan_as_null is DEPRECATED and has no effect. Please avoid using it; it will be removed in a future release". nan_as_null has now been removed but the argument is still present in the function call.

The issue was last touched on in 54846. but this was before nan_as_null was supposed to be removed.

Expected Behavior

The argument can be removed if not in use for the sake of clean code.

Installed Versions

v3.0.0.dev0-1976-g6e61cf44ee

[ethandavidlee]

take

[rhshadrach]

Thanks for the report. As mentioned in the linked PR, it is not to be removed for 3.0.

#54846 (comment)

Also, I think it should not be removed until the upstream issue is closed.

data-apis/dataframe-api#125 (comment)

Finally, pandas is planning to deprecate the entire protocol, so I think we can just leave this as is.

#56732 (comment)

I think we're good to add the deprecation for the entire protocol in 3.0, but checking in the above issue. If you'd like to work on that, it'd be a great help!