code: function defineImmutable(target, values) {
      Object.keys(values).forEach(function(key){
        Object.defineProperty(target, key, {
          configurable: false,
          enumerable: true,
          value: values[key]
        });
      });
      return target;
    }
docs: Define immutable properties on a target object
  
  @param {Object} target - An object to be extended
  @param {Object} values - An object of properties
  @return {Object} The target object