d = dict(x=1)Is transformed to
d = dict(x=1)(Yes. There are 13 spaces between the d and the :.) The code is checked into the Python sandbox under refactor. I had a bunch of helpful conversations and did a little pair programming with Martin von Loewis.
if "x" in d :
Guido wrote a summary post about the Python 3000 sprint work. Update: I fleshed out many of the details in several subsequent posts.