Some review of dv_range.patch:

- repr(d.keys()) depends on the internal ordering of items, their hash
values, the insertion order... the test seems fragile.
Or you may rely on the fact that ints are their own hash values, so a
small dict containing small keys will appear ordered. I suggest
something like {6: 1.2, 1: 'A', 7: 42, 4: None}

- empty dicts or empty ranges will display:
   <range: >
   <dict_items: >
Isn't there a better repr? At least this should appear in the tests.