You are an expert in writing code in many different languages. Your goal is to perform code completion for the following code, keeping in mind the rest of the code and the file meta data.
    Metadata details:
    filename: example.go
    path of file: ./repos/do/examples/shutdownable
    
    the code of the file until where you have to start completion: package main

import (
	"log"

	"github.com/samber/do"
)

/**
 * Wheel
 */
type Wheel struct {
}

/**
 * Engine
 */
type Engine struct {
}

func (c *Engine) Shutdown() error {
	println("engine stopped")
	return nil
}

/**
 * Car
 */
type Car struct {
	Engine *Engine
	Wheels []*Wheel
}

func (c *Car) Shutdown() error {
	println("car stopped")
	return nil
}

func (c *Car) Start() {
	println("vroooom")
}

/**
 * Run example
 */
func main() {
	injector := do.New()

	// provide wheels
	do.ProvideNamedValue(injector, "wheel-1", &Wheel{})
	do.ProvideNamedValue(injector, "wheel-2", &Wheel{})
	do.ProvideNamedValue(injector, "wheel-3", &Wheel{})
	do.Provide
    
func main() {
	injector := do.New()

	// provide wheels
	do.ProvideNamedValue(injector, "wheel-1", &Wheel{})
	do.ProvideNamedValue(injector, "wheel-2", &Wheel{})
	do.ProvideNamedValue(injector, "wheel-3", &Wheel{})
	do.ProvideNamedValue(injector, "wheel-4", &Wheel{})

	// provide car
	do.Provide(injector, func(i *do.Injector) (*Car, error) {
		car := Car{
			Engine: do.MustInvoke[*Engine](i),
			Wheels: []*Wheel{
				do.MustInvokeNamed[*Wheel](i, "wheel-1"),
				do.MustInvokeNamed[*Wheel](i, "wheel-2"),
				do.MustInvokeNamed[*Wheel](i, "wheel-3"),
				do.MustInvokeNamed[*Wheel](i, "wheel-4"),
			},
		}

		return &car, nil
	})

	// provide engine
	do.Provide(injector, func(i *do.Injector) (*Engine, error) {
		return &Engine{}, nil
	})

	// start car
	car := do.MustInvoke[*Car](injector)
	car.Start()

	err := injector.ShutdownOnSIGTERM()
	if err != nil {
		log.Fatal(err.Error())
	}
}