code: @Override
      public PurchaseHostReservationResult purchaseHostReservation(PurchaseHostReservationRequest request) {
          request = beforeClientExecution(request);
          return executePurchaseHostReservation(request);
      }
docs: <p>
  Purchase a reservation with configurations that match those of your Dedicated Host. You must have active
  Dedicated Hosts in your account before you purchase a reservation. This action results in the specified
  reservation being purchased and charged to your account.
  </p>
  
  @param purchaseHostReservationRequest
  @return Result of the PurchaseHostReservation operation returned by the service.
  @sample AmazonEC2.PurchaseHostReservation
  @see <a href="http://docs.aws.amazon.com/goto/WebAPI/ec2-2016-11-15/PurchaseHostReservation" target="_top">AWS
  API Documentation</a>