//   use them in new code.
// - Every node in the function's body must have all of its inputs (including
//   control inputs). In other words, for every node in the body, each input
//   must be either listed in `inputs` or must come from another node in
//   the body. In particular, it is an error to have a control edge going from
//   a node outside of the body into a node in the body. This applies to control