Python generic type annotation for pandas series

Question

I am encountering a type checking error when running my code through typeguard.

I the following file in my package:

from __future__ import annotations
import pandas as pd

def col_sum(x: pd.Series[float]) -> pd.Series[float]:
   return x*(x.sum()-1)

Originally, I was using pd.Series for these type-hints, but when I run my code through mypy it requires that I explicitly subscript a type on the generic type, so I changed it to pd.Series[float] (this makes sense as it is more explicit and allows mypy to be certain that x.sum() is a float).

I also have a test script which performs some unit tests on this function.

However, my test-suite also includes running pytest --typeguard-packages={MyPackage}, but this is failing due to this function. Here is the error:

>   def col_sum(x: pd.Series[float]) -> pd.Series[float]:
E   TypeError: 'type' object is not subscriptable

From my understanding, this is because mypy is importing the pd.Series from the pandas-stubs package which is a generic type (thus the requirement for the subscript). But pytest passes my code through the install_import_hook() function from typeguard which imports pd.Series as a class/type from the regular pandas package (which cannot be subscripted).

How can I make my code pass both of these tests?

For clarity, I am using a trimmed down version of the hypermodern cookiecutter template. I am using nox to manage my test-suite, and it runs the following Sessions:

* pre-commit -> Lint using pre-commit.
* safety -> Scan dependencies for insecure packages.
* mypy-3.10 -> Type-check using mypy.
* mypy-3.11 -> Type-check using mypy.
* tests-3.10 -> Run the test suite.
* tests-3.11 -> Run the test suite.
* coverage -> Produce the coverage report.
* typeguard -> Runtime type checking using Typeguard.
* xdoctest-3.10 -> Run examples with xdoctest.
* xdoctest-3.11 -> Run examples with xdoctest.
* docs-build -> Build the documentation.

All of which are passing, except for typeguard Relevant package versions:

python = "3.10.11"
pandas = "2.1.4"
pandas-stubs = "2.1.4.231218"
typeguard = "4.1.5"
pytest = "7.4.3"