code: static int getInvocationArgsCount(Node invocation) {
      if (invocation.isTaggedTemplateLit()) {
        Iterable<Node> args = new TemplateArgsIterable(invocation.getLastChild());
        return Iterables.size(args) + 1;
      } else {
        return invocation.getChildCount() - 1;
      }
    }
docs: Returns the number of arguments in this invocation. For template literals it takes into
  account the implicit first argument of ITemplateArray