code: function addPagesTooling( api ) {
     let pagesTooling;
     Object.defineProperty( api, 'pages', {
        get() {
           if( !pagesTooling ) {
              pagesTooling = createPagesTooling( api );
              pagesTooling.enable();
              api.destroy = () => {
                 pagesTooling.disable();
              };
           }
           return pagesTooling;
        }
     } );
  }
docs: //////////////////////////////////////////////////////////////////////////////////////////////////////////// 
  Add a getter to create the old interface on demand.
  
  @param {AxTooling} api
  the tooling instance to enrich with the pages tooling
  @private