docs: def mono_parser(cards: list) -> Optional[list]:
      '''
      parser for MONO [8] issue mode
      MONO = 0x08; // All card transaction amounts are equal to 1
      '''
      from pypeerassets.pautils import exponent_to_amount, amount_to_exponent
  
      processed_cards = []
      decimals = cards[0].number_of_decimals
  
      for c in cards:
          c.amount = [amount_to_exponent(
                       exponent_to_amount(c.amount[0], decimals),
                       decimals)]
          processed_cards.append(c)
  
      return processed_cards