def previous_friday(dt):
    """
    If holiday falls on Saturday or Sunday, use previous Friday instead.
    """
    if dt.weekday() == 5:
        return dt - timedelta(1)
    elif dt.weekday() == 6:
        return dt - timedelta(2)
    return dt
dataset/ETHPy150Open pydata/pandas/pandas/tseries/holiday.py/previous_friday/original