There's a lot of not quite magic, but stuff that doesn't seem to come really straight out of the API directly. So we want our methods from reading or code, you should be able to understand what should go in there. And that's where I think we're going to talk about this later, but that's where expression is. We also only return a single type from a from a method and we only a dot filter just expects aBoolean expression that produces a Boolean, not an integer, not a string.