def METHOD_NAME(self, instance, cleaned_choices):
    removed_hashes = []
    final_hashes = [c["hash"] for c in cleaned_choices]
    for choice in instance.choices:
        if choice["hash"] not in final_hashes:
            instance.votes -= choice["votes"]
            removed_hashes.append(choice["hash"])
    if removed_hashes:
        instance.pollvote_set.filter(choice_hash__in=removed_hashes).delete()