Python: __str__, but for a class, not an instance?

I understand the following Python code:

>>> class A(object):
...     def __str__(self):
...         return "An instance of the class A"
... 
>>> 
>>> a = A()
>>> print a
An instance of the class A

Now, I would like to change the output of

>>> print A
<class '__main__.A'>

Which function do I need to overload to be able to do that? The solution has to work even if the class is never instantiated. Is the situation different in Python 2.x and 3?