code: Optional<PackingPlan.InstancePlan> getInstance(String componentName, int componentIndex) {
      for (PackingPlan.InstancePlan instancePlan : this.instances) {
        if (instancePlan.getComponentName().equals(componentName)
            && instancePlan.getComponentIndex() == componentIndex) {
          return Optional.of(instancePlan);
        }
      }
      return Optional.absent();
    }
docs: Return the instance of componentName with a matching componentIndex if it exists
  
  @return an optional including the InstancePlan if found