code: def iso13616Prepare(iban):
      
      A = ord("A")
      Z = ord("Z")
  
      iban = iban.upper()
      iban = iban[4:] + iban[:4]
  
      def charfunc(n):
          code = ord(n)
          if code >= A and code <= Z:
              return str(code - A + 10)
          else:
              return str(n)
  
      return "".join(map(charfunc, list(iban)))
docs: Prepare an IBAN for mod 97 computation by moving the first
      4 chars to the end and transforming the letters to numbers
      (A = 10, B = 11, ..., Z = 35), as specified in ISO13616.
  
      @method iso13616Prepare
      @param {String} iban the IBAN
      @returns {String} the prepared IBAN