input: Write a python function to determine if an object is an instance of a class or of a subclass thereof.
  assert is_instance_of_class_or_subclass(Watcher, object) == True
  assert is_instance_of_class_or_subclass(Watcher, threading.Thread) == False
  assert is_instance_of_class_or_subclass(Watcher.GroupState, Watcher) == False
output: def is_instance_of_class_or_subclass(obj, cls):
      return isinstance(obj, cls)