I agree that it's a violation of the “one and only one” maxim, but that maxim is a bit hard to take as an absolute. I think the problem is that there are already a lot of ways to write things in Python, the biggest example that comes to mind is list comprehensions.

    outputs = [f(x) for x in inputs]

Versus:

    outputs = []
    for x in inputs:
        outputs.append(f(x))

The assignment expression lets you:

    outputs = [y for x in inputs
               if (y := f(x)) is not None]

I know that more complicated list comprehensions in Python are a bit of a sore point for some people, but I would say that they’re also inherently unpythonic, and I like them.