Python code to generate the MRZ from the passport data. It also corrects a padding error

mrz.py

from itertools import cycle


def add_checksum(value):
    s = sum(
        w * int(v, 36) for i, (v, w) in enumerate(zip(value, cycle([7, 3, 1])))
    )
    return f"{value}{s % 10}"


def mrz(pp_nr, dob, expiry, sex, country):
    """
    Machine-readable zone of passport.  dob and expiry are formatted as YYMMDD.
    sex is M, F, or <.  country is a 3-letter code.
    """
    pp_cs = add_checksum(pp_nr)
    dob_cs = add_checksum(dob)
    expiry_cs = add_checksum(expiry)
    mrz_cs = add_checksum(f"{pp_cs}{dob_cs}{expiry_cs}")
    return f"{pp_cs}{country}{dob_cs}{sex}{expiry_cs}{mrz_cs[-1]:<>16}"


print(mrz("123456789", "841213", "220229", "M", "XXX"))