Immutable Sequence of float with length 3 as argument

[RubendeBruin]

I need some guidance on implementing type-hinting for 3d vectors.

We are trying to add type-hits to our 3d vector math functions. Many of these functions require a sequence of 3 floats as input. For example:

def to_global(point : tuple[float, float, float]) -> ....:

tuple[float, float, float] defines all that we need: The input argument shall have three indexable elements point[0], point[1], point[2] and their values shall be float.

Issue is that while duck-type compatible is also fine as input: so [1,2,3] (list of int) would also work without issues:

b = to_global([1,2,3])

but in those case the type checker does raise a warning about incompatible types.

From the best practices I read that in cases like this a Generic type would be preferable:

def to_global(point : Sequence[float]) -> ....:

but that does not cover the length.

If I now try:

b = to_global([1,2])

the type checker no longer warns, but the code does not run as point[2] is not available.

Is there a way to get the best of both? Ie the strictness of tuple[float, float, float] but without the type-checker complaining when trying to pass a duck compatible input argument?

Bonus:
I would also like to hint that the values of the input argument are not mutated, (like const in c).