remove previous globex day from df

def session(df, start='17:00', end='16:00'):
    """ remove previous globex day from df """
    if df.empty:
        return df

    # get start/end/now as decimals
    int_start = list(map(int, start.split(':')))
    int_start = (int_start[0] + int_start[1] - 1 / 100) - 0.0001
    int_end = list(map(int, end.split(':')))
    int_end = int_end[0] + int_end[1] / 100
    int_now = (df[-1:].index.hour[0] + (df[:1].index.minute[0]) / 100)

    # same-dat session?
    is_same_day = int_end > int_start

    # set pointers
    curr = prev = df[-1:].index[0].strftime('%Y-%m-%d')

    # globex/forex session
    if not is_same_day:
        prev = (datetime.strptime(curr, '%Y-%m-%d') -
                timedelta(1)).strftime('%Y-%m-%d')

    # slice
    if int_now >= int_start:
        df = df[df.index >= curr + ' ' + start]
    else:
        df = df[df.index >= prev + ' ' + start]

    return df.copy()