code: function() {
      this.options.viewType = utils.arrayify(this.options.viewType || []);
      if (this.options.viewType.length === 0) {
        this.options.viewType.push('renderable');
      }
      return this.options.viewType;
    }
docs: Set view types for the collection.
  
  @param {String} `plural` e.g. `pages`
  @param {Object} `options`
  @api private