If holiday falls on Saturday, use day before (Friday) instead;
    if holiday falls on Sunday, use day thereafter (Monday) instead.

def nearest_workday(dt):
    """
    If holiday falls on Saturday, use day before (Friday) instead;
    if holiday falls on Sunday, use day thereafter (Monday) instead.
    """
    if dt.weekday() == 5:
        return dt - timedelta(1)
    elif dt.weekday() == 6:
        return dt + timedelta(1)
    return dt