// KeyFile path of your key file you generated at PREPARATION section 
	const KeyFile = "/path/to/identity.json"

	// SpreadsheetID is identity string of spreadsheet that you want to manipulate. Refer: https://developers.google.com/sheets/api/guides/concepts
	const SpreadsheetID = "1234567890qwertyuiopASDFGHJKL"

	// SheetName is a name of a sheet you want to manipulate 
	SheetName = "book"

	// Init Senmai Client
	sm, err := senmai.New(KeyFile)
	if err != nil {
		log.Fatal(err.Error())
	}

	// Get Table struct that named "book"
	book, err := sm.GetTable(SpreadsheetID, SheetName)
	if err != nil {
		log.Fatal(err.Error())
	}

	// Fetch
	row, err := book.FetchRow("mybook0001")
	if err != nil {
		log.Fatal(err.Error())
	}
	fmt.Printf("%#v\n", row)

	// Update
	row.Cols["price_yen"] = "4000"
	err = row.Update()
	if err != nil {
		log.Fatal(err.Error())
	}

	// Build a new row struct
	b1 := book.NewRow()

	// Fill-in field values
	b1.Cols = map[string]string{
		"id":         "mybook0003",
		"name":       "Slack: Getting Past Burnout, Busywork, and the Myth of Total Efficiency",
		"author":     "Tom DeMarco",
		"price_yen":  "2800",
	}

	// Insert into spreadsheet
	err = b1.Insert()
	if err != nil {
		log.Fatal(err.Error())
	}