func GenerateUUID(fn func([]byte) string) string {
	f, e := os.OpenFile("/dev/urandom", os.O_RDONLY, 0)
	defer f.Close()
	if e != nil {
		return ""
	} else {
		b := make([]byte, 16)
		f.Read(b)
		return fn(b)
	}
}
Generate a universally unique identifier (UUID) using the computer's
/dev/urandom output as a randomizer, returning a string specified by
the given formatting function
package barcodes
import (
	"fmt"
	"os"
)
const (
	UPC  = "UPC"
	EAN  = "EAN"
	ISBN = "ISBN"
)
var (
	DashedUUID = func(b []byte) string {
		return fmt.Sprintf("%x-%x-%x-%x-%x", b[0:4], b[4:6], b[6:8], b[8:10], b[10:])
	}
	UndashedUUID = func(b []byte) string {
		return fmt.Sprintf("%x", b)
	}
)