Generating and validating Luhn numbers in GO

import (
  "github.com/joeljunstrom/go-luhn"
  "fmt"
)

// Checking if a string is a valid luhn
luhn.Valid("1234") //= false
luhn.Valid("562246784655") //= true

// Generating a valid luhn string of a specified size
randomLuhn := luhn.Generate(12)
fmt.Println(randomLuhn) //= "802252051072"

// Generating a valid luhn string of a specified size
// with a given prefix
randomLuhnWithPrefix := luhn.GenerateWithPrefix(10, "12345")
fmt.Println(randomLuhnWithPrefix) //= "1234533220"