I want to do something like this:

    hashlib.md5(json.dumps(d, sort_keys=True))

So I can check if a dict's contents are the same as a DB version, but I can't guarantee that all the keys are strings, so it breaks, annoyingly. I would very much like the apply-default-function-then-sort approach. Until then, my work-around is this:

    def deep_stringize_dict_keys(item):
        """Converts all keys to strings in a nested dictionary"""
        if isinstance(item, dict):
            return {str(k): deep_stringize_dict_keys(v) for k, v in item.items()}

        if isinstance(item, list):
            # This will check only ONE layer deep for nested dictionaries inside lists.
            # If you need deeper than that, you're probably doing something stupid.
            if any(isinstance(v, dict) for v in item):
                return [deep_stringize_dict_keys(v) if isinstance(v, dict) else v
                        for v in item]

        # I don't care about tuples, since they don't exist in JSON

        return item

Maybe it can be of some use for others.