This will only work on Python 2:

.. skip: next if(sys.version_info >= (3, 0), reason="only true on python 2")

>>> repr(u'foo')
"u'foo'"

This should run:

>>> run.append(1)

This will only parse on Python 3:

.. skip: start if(sys.version_info < (3, 0), reason="only true on python 3")

.. code-block:: python

    def myfunc(*, keyword_only):
         return keyword_only

>>> myfunc(keyword_only='hello')
'hello'

>>> def myfunc2(*, keyword_only): pass

.. skip: end

This should also run:

>>> run.append(2)