[Python] python type annotation of SpecialForms with pydantic and mypy

python 3.13 pydantic 2.10.5 mypy 1.16.0

how to properly annotate return of typing._SpecialForm, specifically typing.Annotated? I'm using mypy as type checker.

from functools import partial
from typing import Annotated

from pydantic import AfterValidator, BaseModel


def validate_smth(value: str, context: str) -> str:
if value == "test":
print(f"Validated {value}")
else:
raise ValueError(f"Value {value} is not allowed in context {context}")
return value


def return_annotated_type(context: str = "") -> type: # error: Incompatible return value type (got "<typing special form>", expected "type") [return-value]
validator = partial(validate_smth, context=context)
return Annotated[str, AfterValidator(validator)]


class MyModel(BaseModel):
field: return_annotated_type(context="test") # error: Invalid type comment or annotation [valid-type]
# note: Suggestion: use return_annotated_type[...] instead of return_annotated_type(...)

MyModel.model_validate({"field": "test"})



I tried:

def return_annotated_type(context: str = "") -> Annotated[str, AfterValidator]:
# error: Incompatible return value type (got "<typing special form>", expected "str") [return-value]


def return_annotated_type(context: str = "") -> Any:
# no error here, but i don't like that Any is too broad.

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