I think in the descriptor howto, at this point:

>>> class MyClass(object):
    x = RevealAccess(10, 'var "x"')
    y = 5

or the prompt should not have been, or there is a wrong indentation.
Furthermore, in Python 3:

http://docs.python.org/3/howto/descriptor.html

we can remove the explicit derivation from `object`

Maybe is better to underline the difference between classes and non-classes objects, instead of between objects and classes, because a class is an object, so it could be confusing). 
Raymond, what do you think about rewriting this sentence:

  `The details of invocation depend on whether obj is an object or a class.`

as:

  `The details of invocation depend on whether obj is a class or not.`

I upload two new patches (one for py2 and the other for py3)

I saw right now your decision about keeping object in the Python 3 doc:

http://bugs.python.org/issue17351#msg183870

So, now the py3 patch takes in account just the indentation of the `RevealAccess` example and the "class or not" suggestion.

The indentation is not incorrect.  What you're seeing is normal for the interactive prompt.

Also, it is not incorrect to inherit from object in Python 3.
There is some value in keeping the document the same between versions.

I think the indentation is a problem, for several reasons. In all the examples in the documentation, the form by using the interactive shell is the following:

    >>> class MyClass:
    ...     pass

otherwise:

    class MyClass:
        pass

This one is awful:

>>> class MyClass:
    pass

and in fact it is no used in the doc. So if you want to put the class clause in the interactive shell, you have to add the dots to indent the suite of the compound statement, in order to be consistent with the rest of all the documentation.
But it is not just a problem of beauty:

$ python -m doctest descriptor.rst 
**********************************************************************
File "descriptor.rst", line 165, in descriptor.rst
Failed example:
    class MyClass(object):
Exception raised:
    ...
        class MyClass(object):
                             ^
    SyntaxError: unexpected EOF while parsing
...

By applying the patch, the definitions of the classes RevealAccess and MyClass pass the documentation test. The whole example does not pass in any case, because you are not consistent using the shell notation.

By looking at the other examples in the howto, I saw there is the same problem in all the definitions in the prompt, and furthermore, we are using a different number of spaces to indent MyClass respect the rest of the classes defined in the prompt. 
There is also a wrong indentation in the StaticMethod definition (no prompt definition):

class StaticMethod(object):
 "Emulate PyStaticMethod_Type() in Objects/funcobject.c"

 def __init__(self, f):
      self.f = f

 def __get__(self, obj, objtype=None):
      return self.f

Applying the py3full.patch, the howto passes all the documentation tests:

$ python -m doctest descriptor.rst | tail -n 1
***Test Failed*** 18 failures.
$ python -m doctest descriptor_modified.rst | tail -n 1
$


My 2 cents

In the latest patch there are 5-spaces indents in several places.

You are right. Now it should be ok

By the way, it does not pass all the tests in Python 2.7:

$ python2.7 -m doctest descriptor_modified.rst | tail -n 1
***Test Failed*** 3 failures.

If we want to be very rigorous, in order to pass the tests in Py2.7 too (kipping the rst aligned between py2 and py3), we have to add 3 others doctest: +SKIP directives. 

PS. I think there is a small bug in sphinx, related to our examples:

https://bitbucket.org/birkenfeld/sphinx/issue/1271/doctest-directive-and-dots-not-hidden

$ python -c "import this" | grep "silently"
Errors should never pass silently