python-validators/src/validators/iban.py at master · sysfce2/python-validators · GitHub

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"""IBAN."""

# standard

import re

# local

from .utils import validator

def _char_value(char: str):

"""A=10, B=11, ..., Z=35."""

return char if char.isdigit() else str(10 + ord(char) - ord("A"))

def _mod_check(value: str):

"""Check if the value string passes the mod97-test."""

# move country code and check numbers to end

rearranged = value[4:] + value[:4]

return int("".join(_char_value(char) for char in rearranged)) % 97 == 1

@validator

def iban(value: str, /):

"""Return whether or not given value is a valid IBAN code.

Examples:

>>> iban('DE29100500001061045672')

# Output: True

>>> iban('123456')

# Output: ValidationError(func=iban, ...)

Args:

value:

IBAN string to validate.

Returns:

(Literal[True]): If `value` is a valid IBAN code.

(ValidationError): If `value` is an invalid IBAN code.

"""

return (

(re.match(r"^[a-z]{2}[0-9]{2}[a-z0-9]{11,30}$", value, re.IGNORECASE) and _mod_check(value))

if value

else False

)