code: @Override
      public UpdateStackSetResult updateStackSet(UpdateStackSetRequest request) {
          request = beforeClientExecution(request);
          return executeUpdateStackSet(request);
      }
docs: <p>
  Updates the stack set, and associated stack instances in the specified accounts and regions.
  </p>
  <p>
  Even if the stack set operation created by updating the stack set fails (completely or partially, below or above
  a specified failure tolerance), the stack set is updated with your changes. Subsequent
  <a>CreateStackInstances</a> calls on the specified stack set use the updated stack set.
  </p>
  
  @param updateStackSetRequest
  @return Result of the UpdateStackSet 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.
  @throws StackInstanceNotFoundException
  The specified stack instance doesn't exist.
  @sample AmazonCloudFormation.UpdateStackSet
  @see <a href="http://docs.aws.amazon.com/goto/WebAPI/cloudformation-2010-05-15/UpdateStackSet" target="_top">AWS
  API Documentation</a>