code: function(model, options) {
              options || (options = {});
              if (!(model instanceof Model)) {
                  var attrs = model;
                  options.collection = this;
                  model = new this.model(options, attrs);
              } else if (!model.collection) {
                  model.collection = this;
              }
              return model;
          }
docs: /*
  Prepare a model or hash of attributes to be added to this collection.