None Python error/bug?

Question

In Python you have the None singleton, which acts pretty oddly in certain circumstances:

>>> a = None
>>> type(a)


        

Answer 1

None is a value(instance) and not a type. As the error message shows, isinstance expects the second argument to be a type.

The type of None is type(None), or Nonetype if you import it (from types import NoneType)

Note: the idiomatic way to do the test is variable is None. Short and descriptive.