Implementation of NoneType, Reasons and Details

Question

I recently read somewhere that the special value None in python is a singleton object of its own class, specifically NoneType. This explained a lot

Answer 1

1. The NoneType overrides __new__ which always return the same singleton. The code is actually written in C so dis cannot help, but conceptually it's just like this.

2. Having only one None instance is easier to deal with. They are all equal anyway.

3. By overriding __new__... e.g.

   class MyNoneType(object):
       _common_none = 0
       def __new__(cls):
           return cls._common_none
   
   MyNoneType._common_none = object.__new__(MyNoneType)
   
   m1 = MyNoneType()
   m2 = MyNoneType()
   print(m1 is m2)