Substance Designer Python API: how do I make an Input node become Float4?

I can already create a graph input parameter of type Float4 through Python.

The problem is different:

I cannot make the corresponding Input node become Float4.

What I need is the Designer UI Input node whose editor shows 4 float components, not just a graph parameter of type Float4.

What I observed:

Creating the graph input as Float4 works

Creating the Input node works

But the Input node still behaves as a plain float/value input, not as a Float4 input

So my question is:

Through the Substance Designer Python API, is it possible to change the type of an Input node to Float4?

More specifically:

Is there an API call to set the Input node type to Float4?

If not, is the node type determined only when the node is created?

If it is possible, what is the correct Python API sequence?

I am asking about the Input node type itself, not the graph input parameter type.