[Python] How to inherit from Python None

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

I tried this:

class InvalidKeyNone(None):
pass


but that gives me:

TypeError: Error when calling the metaclass bases
cannot create 'NoneType' instances


What would be the correct solution that gives me a type that behaves exactly like None but which I can type test?

foo = InvalidKeyNone()
print(type(foo))
>>> InvalidKeyNone


I want to do this because I am creating a selection scheme on Python datastructures:

bar = select(".foo.bar.[1].x", {"foo":{"bar":[{"x":1}, {"x":2}], "baz":3})
print(bar)
>> 2


And I want to be able to distinguish whether I get a None because the selected value is None or because the key was not found.

However, it must return a (ducktyped) None that behaves exactly like a None. No exceptions or custom type returning here.

I really want the default behavior to have it return a None when the key is not present.

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