Series.keys() should return an Index and not a list

[ClementPinard]

Describe the bug

a = pd.Series({0:0, 1:1})
reveal_type(a.keys()
print(type(a.keys())

Running pyright on this code gives you

information: Type of "a.keys()" is "list[Unknown]"

Which is normal since it's written explictly here :

pandas-stubs/pandas-stubs/core/series.pyi

Line 655 in 583d198

def keys(self) -> list: ...

However, if we run it with python, we get pandas.core.indexes.base.Index

Should we replace the linked line from list to Index ?

I have a code that is failing type checking because it call a.keys().tolist(), while it does work as intended.

[Dr-Irv]

Thanks for the report.

PR with tests welcome.

[ClementPinard]

Closing, as I do believe it has been solved, thanks @janlodewijk !