А вот как проверить такой пример на валидность card_number = ‘4300000000000000’ => ‘master’, card_number = ‘6500000000000000’ => ‘visa’, card_number = ‘4300000000000goo’ => ‘invalid’, card_number = ‘43000000000000.’ => ‘invalid’?
А вот как проверить такой пример на валидность card_number = ‘4300000000000000’ => ‘master’, card_number = ‘6500000000000000’ => ‘visa’, card_number = ‘4300000000000goo’ => ‘invalid’, card_number = ‘43000000000000.’ => ‘invalid’?