shortuuid.go
func NewWithAlphabet(abc string) string {
	enc := base57{newAlphabet(abc)}
	return enc.Encode(uuid.New())
}
func NewWithAlphabet(abc string) string {
	enc := base57{newAlphabet(abc)}
	return enc.Encode(uuid.New())
}
// NewWithAlphabet returns a new UUIDv4, encoded with base57 using the
// alternative alphabet abc.