code: @Override
      public DeleteStackInstancesResult deleteStackInstances(DeleteStackInstancesRequest request) {
          request = beforeClientExecution(request);
          return executeDeleteStackInstances(request);
      }
docs: <p>
  Deletes stack instances for the specified accounts, in the specified regions.
  </p>
  
  @param deleteStackInstancesRequest
  @return Result of the DeleteStackInstances operation returned by the service.
  @throws StackSetNotFoundException
  The specified stack set doesn't exist.
  @throws OperationInProgressException
  Another operation is currently in progress for this stack set. Only one operation can be performed for a
  stack set at a given time.
  @throws OperationIdAlreadyExistsException
  The specified operation ID already exists.
  @throws StaleRequestException
  Another operation has been performed on this stack set since the specified operation was performed.
  @throws InvalidOperationException
  The specified operation isn't valid.
  @sample AmazonCloudFormation.DeleteStackInstances
  @see <a href="http://docs.aws.amazon.com/goto/WebAPI/cloudformation-2010-05-15/DeleteStackInstances"
  target="_top">AWS API Documentation</a>