code: func generalizedWhereLabel(funcName string, containers Context, label string, test func(string, bool) bool) (Context, error) {
  	selection := make([]*RuntimeContainer, 0)
  
  	for i := 0; i < len(containers); i++ {
  		container := containers[i]
  
  		value, ok := container.Labels[label]
  		if test(value, ok) {
  			selection = append(selection, container)
  		}
  	}
  
  	return selection, nil
  }
docs: // generalized whereLabel function