Why are so many built-in types inheritable?

[Fabiano Sidler]

Hi folks!

For debugging purposes I tried this:

--- snip ---
def foo(): pass
function = type(foo)

class PrintingFunction(function):
  def __init__(self, func):
    self.func = func
  def __call__(self, *args, **kwargs):
    print args, kwargs
    return function.__call__(self, args, kwargs)

class DebugMeta(type):
  def __new__(self, name, bases, dict):
    for name in dict:
      if type(dict[name]) is function:
        dict[name] = PrintingFunction(dict[name])

--- snap ---

Now I tought I were able to let all maethod of classes with DebugMeta as
metaclass print out their arguments. But I got the following sad error:

TypeError: Error when calling the metaclass bases
    type 'function' is not an acceptable base type

That's awful, isn't it?
What could I do to get the above code working? (No, I disliked to re-
implement <type 'function'> without this unpleasant behaviour in Python.)

Greetings,
F. Sidler