test_foo.py

from dataclasses import dataclass
from typing import Protocol, Optional, TypeVar, Type


class Animal(Protocol):
    name: str


@dataclass
class Mammal:
    name: str


lookup_types = {Animal: Mammal}

T = TypeVar('T')


def main(lookup_type: Type[T]) -> Optional[Type]:
    lt = lookup_type.get(lookup_type)
    return lt


main(lookup_type=Animal)