issue in adding new row cell in grapejs not working

i am using grapejs version 0.14.33 with angular 6 i want to add a section with 2 blocks on block manager as created on grapejs demo. and for that following code mentioned below but it is not working . suggest me any code that can add a box with 2 section and sections are dragable.

  label: '2 Columns',
  content: '<div class="row" data-gjs-droppable=".row-cell" data-gjs-custom-name="Row">' +
      '<div class="row-cell" data-gjs-draggable=".row"></div>' +
      '<div class="row-cell" data-gjs-draggable=".row"></div>' +
    '</div>',
});