Good information, and well put. A small quibble: you should probably almost never use tuple(), even on recent Python:

    >>> tuple(dict(a=1, b=2).items())
    (('a', 1), ('b', 2))
    >>> tuple(dict(b=2, a=1).items())
    (('b', 2), ('a', 1))

Of course, if you can absolutely guarantee how the dictionary has been constructed, it is possible. No rules are absolute. But in my experience, frozenset() is probably better:

    >>> frozenset(dict(a=1, b=2).items())
    frozenset({('b', 2), ('a', 1)})
    >>> frozenset(dict(b=2, a=1).items())
    frozenset({('b', 2), ('a', 1)})

(Or sometimes even id(), as, if you are confident enough that the dictionary is identical, that might be because it came from the same place. If you are building a reverse dictionary, say, or a cache of indices. Though obviously that it is much more situationally dependent.)