I ran into a bit of a nasty surprised when I realized some of my Delayed objects resulted in a different token when I called tokenize(). This is because in my data I had some objects which didn't have __dask_tokenize__. I fixed those errors, but I'm afraid they might come up again silently. It would be amazing if I could set a flag that would raise an error any time that I tried to tokenize something which contained anything that couldn't be tokenized deterministically. I'm thinking something in dask.base.normalize_object that raises an error instead of returning uuid.uuid4().hex.

Thanks!