Function python_keyword_argument_label 

pub fn python_keyword_argument_label(node: Node<'_>) -> bool

Whether node is the label of a keyword argument: the x in f(x=1).

The label names a parameter or member at the CALLEE, selected by the call’s target, not by anything bound where the label is written. That is why the occurrence-role adapter in structural.rs classifies it LabelOrKey, whose occurrence class is NonReference, and it is the rule the reference census reads to decide that the label is not a forward-reference probe (#2054).