The data of Shanghai and Shenzhen 300 in PYTHON baostock, why is the file empty, with only one line of title and no data? Help, thank you.
RS = bs . query _ history _ k _ data(" sh . 399300 "，" date，code，close，peTTM，turn，"，start_date='2020-04-0 1 '，end_date='2020-05-29 '，frequency="d "，adjustflag="3 ")
Change the above sentence into the following sentence.
RS = bs . query _ history _ k _ data(" SZ . 399300 "，" date，code，close，peTTM，turn "，start_date='2020-04-0 1 '，end_date='2020-05-29 '，frequency="d "，adjustflag="3 ")