code: private static String getQualifiedNameOfFunction(Node function) {
      checkArgument(function.isFunction(), function);
      // The node representing the name (e.g. GETPROP, MEMBER_FUNCTION_DEF, etc.).
      Node lValue = NodeUtil.getBestLValue(function);
      return NodeUtil.getBestLValueName(lValue);
    }
docs: Returns the qualifed name {@code function} is being assigned to.
  
  <p>This implementation abstracts over the various ways of naming a function. ASSIGN need not be
  involved and there may not be a sequence of GETPROPs representing the name.
  
  <p>TODO(b/123354857): Delete this method when naming concepts have been unified. It was created
  as a temporary measure to support ES6 in this pass without becoming blocked on name APIs.