Is it ok to delete items in a Python dict while while iterating over it?

Let's say we have a Python dictionary d, and we're iterating over it like so:

for k, v in d.iteritems():
    del d[f(k)] # remove some item
    d[g(k)] = v # add a new item

(f and g are just some black-box transformations.)

In other words, we try to add/remove items to d while iterating over it using iteritems.

Is this well defined? Could you provide some references to support your answer?

_{See also How to avoid "RuntimeError: dictionary changed size during iteration" error? for the separate question of how to avoid the problem.}