code: public static boolean isSubclassOf(ClassNode classNode, String parentClassName) {
          ClassNode currentSuper = classNode.getSuperClass();
          while (currentSuper != null && !currentSuper.getName().equals(OBJECT_CLASS)) {
              if (currentSuper.getName().equals(parentClassName)) return true;
              currentSuper = currentSuper.getSuperClass();
          }
          return false;
      }
docs: Returns true if the given class name is a parent class of the given class
  
  @param classNode The class node
  @param parentClassName the parent class name
  @return True if it is a subclass