Nodes Type includes single instance

Summary

The provided Nodes type includes signle instances of Nodes.

Nodes = Union[Sequence[N], set[N], N]

That means we can't iterate over a Nodes object. Sequence and set are iterable

Preferred:

Nodes = Union[Sequence[N], set[N]]

Explain your context

(Explain what you did.)

What is the expected correct behavior? What was your goal?

Being able to iterate over Nodes without having to do

nodes = {nodes} if isinstance(nodes, Node)

would provide cleaner code