> So what's really happening is the type expressions are pretending to be "just everyday python", but actually they have arbitrary restrictions (cannot be funct

> So what's really happening is the type expressions are pretending to be "just everyday python", but actually they have arbitrary restrictions (cannot be functions? need to work via overriding `__getitem__`?) that neither you nor I were aware of. Yeah, that sounds about par for the course for bolt-on static-y typing in languages that aren't supposed to be statically typed.