code: func CreateServiceSpec(t *testing.T, opts ...ServiceSpecOpt) swarmtypes.ServiceSpec {
  	t.Helper()
  	var spec swarmtypes.ServiceSpec
  	ServiceWithImage("busybox:latest")(&spec)
  	ServiceWithCommand([]string{"/bin/top"})(&spec)
  	ServiceWithReplicas(1)(&spec)
  
  	for _, o := range opts {
  		o(&spec)
  	}
  	return spec
  }
docs: // CreateServiceSpec creates a default service-spec, and applies the provided options