I know that we can find all models in collection like so, based on attributes

```
var friends = new Backbone.Collection([
              {name: "Athos",      job: "Musketeer"},
              {name: "Porthos",    job: "Musketeer"},
              {name: "Aramis",     job: "Musketeer"},
              {name: "d'Artagnan"},
            ]);
friends.where({job: "Musketeer"});

```

However i want to find the model which doesn have the attribute, or the key. How to do it?
Something like

```
friends.where(not(job));

```

Any help is greatly appreciated