Python docstring type annotation — a class, not an instance?

Question

Let\'s say I have:

class A(object):
   pass

class B(A):
   pass

I want to declare a function that takes a subclass of A as an argument:

Answer 1

All classes are an instance of the type class:

>>> class Foo:
...     pass
... 
>>> type(Foo())

>>> type(Foo)

>>> type(Foo) is type
True

So, a valid answer would be:

:type klass: type