> If instead you add an `elif isinstance(t, str):`, under that condition it'll auto-complete `t.` with all string properties/methods.

now this makes me nervous -- if folks start adding isinstance checks to make their IDE more helpful , we are rally getting away from Duck Typing.

However, you could have presumably typed it as Sequence[int] and gotten all the benefits of duck typing and IDE completion.

However, if code were to really use a duck-typed "str-like" i would produce a failure in the type checker even if it was perfectly functional.

NOTE: str is not a great example, as it's one type that we often do need to explicitly check -- to make the distinction between a Sequence of strings, which a str is, and a str itself.  And str is so fundamental and complex a type it's rarely duck-typed anyway.

-CHB