code: func (builder *STI) PostExecute(containerID, destination string) error {
  	builder.postExecutorStepsContext.containerID = containerID
  	builder.postExecutorStepsContext.destination = destination
  
  	stageSteps := builder.postExecutorFirstStageSteps
  	if builder.postExecutorStage > 0 {
  		stageSteps = builder.postExecutorSecondStageSteps
  	}
  
  	for _, step := range stageSteps {
  		if err := step.execute(builder.postExecutorStepsContext); err != nil {
  			glog.V(0).Info("error: Execution of post execute step failed")
  			return err
  		}
  	}
  
  	return nil
  }
docs: // PostExecute allows to execute post-build actions after the Docker
  // container execution finishes.