code: function prepare (iban) {
    // move front to the back
    iban = iban.slice(4) + iban.slice(0, 4)
  
    // translate letters to numbers
    return iban.split('').map(function (n) {
      var code = n.charCodeAt(0)
      // 65 == A, 90 == Z in ASCII
      if (code >= 65 && code <= 90) {
        // A = 10, B = 11, ... Z = 35
        return code - 65 + 10
      } else {
        return n
      }
    }).join('')
  }
docs: ISO13616 reordering and letter translation NOTE: we assume input is uppercase only based off code from iban.js