def _printable_id_code(self):
        """
        Returns the code in a printable form, filling with zeros if needed.

        :return: the ID code in a printable form
        """
        code = str(self.id_code)
        while len(code) < self._code_size:
            code = '0' + code

        return code
Returns the code in a printable form, filling with zeros if needed.

        :return: the ID code in a printable form