from typing import Any, Tuple

class C1(object):
    pass

class C2(C1):
    pass

class C3(C1):
    pass

_classes={
    "a" : C2,
    "b" : C3
}


def get(desc): # type: (Tuple[str, Any, ...]) -> C1
    return _classes[desc[0]](*desc[1:])