code: function property (model, key) {
    return function (val) {
      return (
        get(val) ? model.get(key) :
        set(val) ? model.set(key, val) :
        (model.on('change:'+key, val), function () {
          model.removeListener('change:'+key, val)
        })
      )}}
docs: /*
  now, lets rewrite our first example