[Python] Python generic type on function getting lost somewhere

Getting this typing error:

error: Incompatible types in assignment (expression has type "object", variable has type "A | B") [assignment]


With this code:

from dataclasses import dataclass
from typing import TypeVar, Mapping, reveal_type


@dataclass
class A:
foo: str = "a"

@dataclass
class B:
bar: str = "b"

lookup_table: Mapping[str, type[A] | type] = {
"a": A,
"b": B
}

reveal_type(lookup_table) # note: Revealed type is "typing.Mapping[builtins.str, Union[type[simple.A], type[simple.B]]]"
T = TypeVar("T")

def load(lookup_table: Mapping[str, type[T]], lookup_key:str) -> T:
con: type[T] = lookup_table[lookup_key]
instance: T = con()
return instance

example_a: A | B = load(lookup_table, "a") # error: Incompatible types in assignment (expression has type "object", variable has type "A | B")
print(example_a)


Edit: Logged a mypy bug here: https://github.com/python/mypy/issues/18265

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