code: function(attrs) {
        // Check for changes of magic fields.
        var model = this;
        var specialFields = ["id", "objectId", "createdAt", "updatedAt"];
        Parse._arrayEach(specialFields, function(attr) {
          if (attrs[attr]) {
            if (attr === "objectId") {
              model.id = attrs[attr];
            } else if ((attr === "createdAt" || attr === "updatedAt") &&
                       !_.isDate(attrs[attr])) {
              model[attr] = Parse._parseDate(attrs[attr]);
            } else {
              model[attr] = attrs[attr];
            }
            delete attrs[attr];
          }
        });
      }
docs: Pulls "special" fields like objectId, createdAt, etc. out of attrs
  and puts them on "this" directly.  Removes them from attrs.
  @param attrs - A dictionary with the data for this Parse.Object.