def utctz_to_altz(utctz: str) -> int:
    """Convert a git timezone offset into a timezone offset west of UTC in seconds
    (compatible with :attr:`time.altzone`).

    :param utctz:
        git utc timezone string, e.g. +0200
    """
    int_utctz = int(utctz)
    seconds = (abs(int_utctz) // 100) * 3600 + (abs(int_utctz) % 100) * 60
    return seconds if int_utctz < 0 else -seconds
Convert a git timezone offset into a timezone offset west of UTC in seconds
    (compatible with :attr:`time.altzone`).

    :param utctz:
        git utc timezone string, e.g. +0200
    
git/objects/util.py