ENH: added finalize to binary operators on DataFrame, GH28283

[seljaks]

• xref Various methods don't call call __finalize__ #28283
• Tests added and passed if fixing a bug or adding a new feature
• All code checks passed.
• Added an entry in the latest doc/source/whatsnew/v1.5.0.rst file if fixing a bug or adding a new feature.

Adds metadata propagation to binary operators on pd.DataFrame
Behavior is consistent with binary operators between two pd.Series i.e. if two DataFrames both have .attrs, result will have .attrs of left-hand operand.
Example:

import pandas as pd
left = pd.DataFrame({"A": [1]})
right = pd.DataFrame({"A": [2]})
left.attrs = {"a": 1}
right.attrs = {"b": 1}
result = left + right
assert result.attrs == left.attrs

If operands are a pd.DataFrame and a pd.Series then result.attrs == pd.DataFrame.attrs regardless of ordering.

[mroeschke]

Could you move this to v1.6.0.rst?

[seljaks]

Moved it to v1.6.0.rst. Wasn't exactly sure where to put it, please let me know if it's ok.

[mroeschke]

Thanks @seljaks