Funny, I ran into the same pattern just a few months ago!

In practice, I found it difficult for coworkers to read and understand so I dropped the idea.

Another limitation I found is that it breaks down when you start using inheritance. For example:

```

class _A: pass

A = NewType("A", _A)

class _B(_A): pass

B = NewType("B", _B)

def foo(a: A) -> None: pass

b = B(_B())

foo(b) # Mypy is not happy: Argument 1 to "foo" has incompatible type "B"; expected "A"

foo(A(b)) # Mypy is OK

```