Personal stylistic opinion here but while the concept of annoations is pythonic, I think the implementation we got is the opposite. It uses magic glyphs that require research to interpret - especially if you come from any other programming language, because when you see things like a : b, or foo -> bar, you expect that to have some syntactic meaning.

The fact that the colon and right arrow in a Python annotation are, for the interpreter, a no-op, is insanely confusing to a newbie or just a generalist. It is compounded by how it would have made much more sense to reserve keywords in their places, so instead of

def foo( a : "fruit", b : Color) -> Pineapple:

you could have used reserved names:

def foo( a expects "fruit", b expects Color) returns Pineapple:

Which is a lot more readable in the way Python is meant to be. Good Python code reads more like prose than software, and the former prevents that from happening at all.