code: function use(namespace, name, fn) {
      name = name || this.name;
      this.temper.require('handlebars').registerHelper(
        namespace + '-' + name,
        fn
      );
  
      return this;
    }
docs: Register provided helper with handlebars.
  
  @param {String} namespace Name of the Pagelet the helper was registered from.
  @param {String} name Registered name
  @param {Function} fn Handlebars helper
  @api public