European Union (Withdrawal) Bill

Will my noble friend allow me to interrupt to check that I have understood what has been said in the last five minutes by both him and the noble Lord, Lord Kerr? As I understand it, the noble Lord, Lord Kerr, said that we cannot have a vacuum and have to have what I would call a treaty. A treaty, in turn, has to be an agreed document. It cannot be just a piece of paper to say that we want to agree with each other; it has to fill the vacuum to which the noble Lord referred. Am I right in my understanding of what is being said?