code: def _java_is_subclass(cls, obj, class_name):
          
          clazz = obj.get_class()
          while clazz:
              if clazz.name == class_name:
                  return True
              clazz = clazz.superclass
          return False
docs: Given a deserialized JavaObject as returned by the javaobj library,
          determine whether it's a subclass of the given class name.