code: func (p *Project) Pull(ctx context.Context, services ...string) error {
  	return p.forEach(services, wrapperAction(func(wrapper *serviceWrapper, wrappers map[string]*serviceWrapper) {
  		wrapper.Do(nil, events.ServicePullStart, events.ServicePull, func(service Service) error {
  			return service.Pull(ctx)
  		})
  	}), nil)
  }
docs: // Pull pulls the specified services (like docker pull).