[Python] How to annotate a Pandas index of datetime.date values using Pandera and mypy?

I'm using Pandera to define a schema for a pandas DataFrame where the index represents calendar dates (without time). I want to type-annotate the index as holding datetime.date values. Here's what I tried:

# mypy.ini
[mypy]
plugins = pandera.mypy


# schema.py
from datetime import date
import pandera as pa
from pandera.typing import Index

class DateIndexModel(pa.DataFrameModel):
date: Index[date]


But running mypy gives the following error:

error: Type argument "date" of "Index" must be a subtype of "bool | int | str | float | ExtensionDtype | <30 more items>" [type-var]
Found 1 error in 1 file (checked 1 source file)


I know that datetime64[ns] or pandas.Timestamp work fine, but I specifically want to model just dates without time. Is there a type-safe way to do this with Pandera and mypy?

Any workaround that lets me enforce date-only index semantics (with or without datetime.date) while keeping mypy happy?

Colab example notebook:
https://colab.research.google.com/drive/1AdiztxHlyvEMo6B3CzYnvzlnh6a0GfUQ?usp=sharing

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