This class extends BasicHookWorker - diffrent from BasicTransformer.
BasicTransformer visits all the nodes in an AST, while BasicHookWorker visits only what you extend.

In this case I want to apply the priority filter to the direct descendants of the parent node if it happens to be a TermCons or a KApp. If it is an Ambiguity node, I want to go over it. But if it is anything else, then stop.