I want to apply the same decorator to every method in a given class, other than those that start and end with __.

It seems to me it should be doable using a class decorator. Are there any pitfalls to be aware of?

Ideally, I'd also like to be able to:

1. disable this mechanism for some methods by marking them with a special decorator
2. enable this mechanism for subclasses as well
3. enable this mechanism even for methods that are added to this class in runtime

[Note: I'm using Python 3.2, so I'm fine if this relies on features added recently.]

Here's my attempt:

_methods_to_skip = {}

def apply(decorator):
  def apply_decorator(cls):
    for method_name, method in get_all_instance_methods(cls):
      if (cls, method) in _methods_to_skip:
        continue
      if method_name[:2] == `__` and method_name[-2:] == `__`:
        continue
      cls.method_name = decorator(method)
  return apply_decorator

def dont_decorate(method):
  _methods_to_skip.add((get_class_from_method(method), method))
  return method

Here are things I have problems with:

• how to implement get_all_instance_methods function
• not sure if my cls.method_name = decorator(method) line is correct
• how to do the same to any methods added to a class in runtime
• how to apply this to subclasses
• how to implement get_class_from_method