from typing import NewType

A = NewType("A", int)
B = NewType("B", str)

def test(x: A | B):
    match x:
        case A():
            print("A")
        case B():
            print("B")

test(A(123))

"""
Traceback (most recent call last):
  File "<stdin>", line 1, in <module>
    test(A(123))
    ~~~~^^^^^^^^
  File "<stdin>", line 3, in test
    case A():
         ~^^
TypeError: called match pattern must be a class
"""