code: function(obj, cache) {
        cache[obj.cid] = obj;
        this.listenToOnce(obj, 'before-dispose', function() {
          delete cache[obj.cid];
        });
      }
docs: Initialize the given object in the given cache.
  @method __initialize
  @param obj {Backbone.Events} any object that implements/extends backbone events.
  @param obj.cid {String} the unique identifier for the object.
  @param cache {Object} the cache to add the object to.
  @private