Update to classmethod

terbilang.py

# tested on python 3.11, but should work on 3.8+


class SaidIndonesian:
    unit = ['', 'satu', 'dua', 'tiga', 'empat', 'lima', 'enam', 'tujuh', 'delapan', 'sembilan', 'sepuluh', 'sebelas']

    @classmethod
    def from_integer(cls, number: int) -> str:
        if number is None:
            return ''
        if number == 0:
            return 'nol'
        word_list = cls._terbilang(number)
        cleaned_word_list = [e for e in word_list if e != '']
        return ' '.join(cleaned_word_list)

    @classmethod
    def _terbilang(cls, number: int) -> List[str]:
        if 0 <= number <= 11:
            return [cls.unit[number]]
        elif 12 <= number <= 19:
            return cls._terbilang(number % 10) + ['belas']
        elif 20 <= number <= 99:
            return cls._terbilang(int(number / 10)) + ['puluh'] + cls._terbilang(number % 10)
        elif 100 <= number <= 199:
            return ['seratus'] + cls._terbilang(number - 100)
        elif 200 <= number <= 999:
            return cls._terbilang(int(number / 100)) + ['ratus'] + cls._terbilang(number % 100)
        elif 1_000 <= number <= 1_999:
            return ['seribu'] + cls._terbilang(number - 1_000)
        elif 2_000 <= number <= 999_999:
            return cls._terbilang(int(number / 1_000)) + ['ribu'] + cls._terbilang(number % 1_000)
        elif 1_000_000 <= number <= 999_999_999:
            return cls._terbilang(int(number / 1_000_000)) + ['juta'] + cls._terbilang(number % 1_000_000)
        elif 1_000_000_000 <= number <= 999_999_999_999:
            return cls._terbilang(int(number / 1_000_000_000)) + ['milyar'] + cls._terbilang(number % 1_000_000_000)
        elif 1_000_000_000_000 <= number <= 999_999_999_999_999:
            return cls._terbilang(int(number / 1_000_000_000_000)) + ['triliun'] + cls._terbilang(number % 1_000_000_000_000)
        else:
            raise ValueError('Too much number')


if __name__ == '__main__':
    print(SaidIndonesian.from_integer(999_999_999_999))