def add_pull_num(df):
    df = df.sort_values(by=['start_time'])
    df.insert(loc=0, column='pull_num', value=(np.arange(len(df)) + 1))
    return df
def add_pull_num(df):
    df = df.sort_values(by=['start_time'])
    df.insert(loc=0, column='pull_num', value=(np.arange(len(df)) + 1))
    return df