added some TODOs
some functions of session is assignment to  FundsDataDB attribute.
invalid origin_date value is processed.
test.py is used to call the fether and DBAPI.
Some exception processing code is added.
1. StockList class is add to map stock_list
2. session.flush function is mapped to self.flush
Fetching the basic information and stock information function is
completed. And the data is fetched.