How to inherit from Python None

Question

I would like to create a class that inherites from None.

Tried this:

class InvalidKeyNone(None):
    pass

but that giv

Answer 1

Subclassing None does not make sense, since it is a singleton and There Can Be Only One. You say you want a class with the same behaviour, but None does not have any behaviour!

If what you really want is a unique placeholder that you can return from a function to indicate a special case then simplest way to do this is to create a unique instance of object:

InvalidKey = object()

result = doSomething()
if result is InvalidKey:
    ...