title: how to sort a datatable frame in descending order
body: <p>I'm trying to apply a sort on one field(total product ratings per each country) in a Frame, and here ascending is worked out, all the products are displayed in an ascending order </p>
  
  <p>I have looked for it(sort options) in documentation, however its info is not written down/available.</p>
  
  <p>a[:,:,sort("totals")]</p>
  
  <p>is there any way to do a descending sort on this field?.</p>