Validate CIF (Romanian VAT number) https://ro.wikipedia.org/wiki/Cod_de_Identificare_Fiscal%C4%83

validate_cif.py

def validate_cif(cif):
    # Remove RO if it was added 
    cif = str(cif).lower().lstrip("ro")
    if not cif.isnumeric():
        # Must be numeric
        return False
    if len(cif) >= 10:
        # Too long
        return False
    if len(cif) <= 1:
        # Too short
        return False

    key = "753217532"

    computed_check_number = sum(
        int(i) * int(j)
        for i, j in zip(cif[::-1][1:], key[::-1])
    ) * 10 % 11
    # Modulo by 10, to handle the case where the check number
    # is 10.
    if computed_check_number % 10 != int(cif[-1]):
        # Self check number isn't correct
        return False

    return True