docs: def convert_to(target, amount, date=None, percent=0, valid_days_max=None):
      """will convert the amount in CZK into given currency (target)
      you can calculate with regard to (given) date
      you can add additional margin with percent parameter
      valid_days_max: see rate()
      """
      if target.upper() == 'CZK':
          result = amount
      else:
          result = amount / rate(target, date, valid_days_max=valid_days_max)
      return modified(result, percent)