handbook: incorrect recipe for "function with parameters"

As I write, the handbook says that the following usage:

zooKeeper.workSchedule = "morning";
zooKeeper(giraffeCage);

should have the following TypeScript declaration

// Note: Function must precede module
function zooKeeper(cage: AnimalCage);
module zooKeeper {
    var workSchedule: string;
}

That doesn't work AFAIK. I believe the recommendation should be:

interface zooKeeper {
  (cage:AnimalCage) : void;
  workSchedule: string;
}

Provide feedback