def aba(self) -> str:
        """Generate an ABA routing transit number."""
        fed_num = self.random_int(min=1, max=12)
        rand = self.numerify("######")
        aba = f"{fed_num:02}{rand}"

        # calculate check digit
        d = [int(n) for n in aba]
        chk_digit = 3 * (d[0] + d[3] + d[6]) + 7 * (d[1] + d[4] + d[7]) + d[2] + d[5]
        chk_digit = ceil(chk_digit / 10) * 10 - chk_digit

        return f"{aba}{chk_digit}"
Generate an ABA routing transit number.
faker/providers/bank/__init__.py