BUG: Series index parameter should accept Sequence[str] (or more general Sequence[Optional[Hashable]]

[bashtage]

import pandas as pd
from typing import Sequence

def f(i: Sequence[str]):
    return pd.Series([1,2,3],index=i)

Error is

exp.py: note: In function "f":
exp.py:4: error: Function is missing a return type annotation
exp.py:5: error: No overload variant of "Series" matches argument types "List[int]", "Sequence[str]"
exp.py:5: note: Possible overload variants:
exp.py:5: note:     def [S1 in (str, bytes, date, datetime, timedelta, bool, int, float, complex, Timestamp, Timedelta, datetime64)] Series(cls, data: DatetimeIndex, index: Union[str, int, Series[Any], List[Any], Index] = ..., dtype: Any = ..., name: Optional[Hashable] = ..., copy: bool = ..., fastpath: bool = ...) -> TimestampSeries
exp.py:5: note:     def [S1 in (str, bytes, date, datetime, timedelta, bool, int, float, complex, Timestamp, Timedelta, datetime64)] Series(cls, data: object, dtype: Type[S1], index: Union[str, int, Series[Any], List[Any], Index] = ..., name: Optional[Hashable] = ..., copy: bool = ..., fastpath: bool = ...) -> Series[S1]
exp.py:5: note:     def [S1 in (str, bytes, date, datetime, timedelta, bool, int, float, complex, Timestamp, Timedelta, datetime64)] Series(cls, data: object = ..., index: Union[str, int, Series[Any], List[Any], Index] = ..., dtype: Any = ..., name: Optional[Hashable] = ..., copy: bool = ..., fastpath: bool = ...) -> Series[Any]

[Dr-Irv]

Can't accept Sequence[str] because a str will match, and you can't write pd.Series([1,2,3], index="abc")

So in your example, f("abc") would pass the type checker on the call to f, but then pandas will not accept the argument at runtime.

Open to other suggestions, but I can't accept your suggested change.

[bashtage]

Going to close as I think the Sequence[str] issue is resolved as not possible. Need concrete container types due to the unfortunate properties of str being a Sequence.