 Right. Then that's typically right. Congress will often intentionally leave that vague because they can't get agreement and they don't have the expertise to say X parts per million measured in the following way. Yada, yada, yada. This is super complicated stuff. Right. So typically it's left to the agencies who will interpret those laws. And there's an elaborate set of procedures by which they adopt rules by which they interpret. They do this. They don't do this just willy nilly.