parameters: (self, setting: dict)
docstring: Start gateway connection.
  
          to implement this method, you must:
          * connect to server if necessary
          * log connected if all necessary connection is established
          * do the following query and response corresponding on_xxxx and write_log
              * contracts : on_contract
              * account asset : on_account
              * account holding: on_position
              * orders of account: on_order
              * trades of account: on_trade
          * if any of query above is failed,  write log.
  
          future plan:
          response callback/change status instead of write_log
docstring_summary: Start gateway connection.
docstring_tokens: Start gateway connection .
function: def connect(self, setting: dict) -> None:
          """
          Start gateway connection.
  
          to implement this method, you must:
          * connect to server if necessary
          * log connected if all necessary connection is established
          * do the following query and response corresponding on_xxxx and write_log
              * contracts : on_contract
              * account asset : on_account
              * account holding: on_position
              * orders of account: on_order
              * trades of account: on_trade
          * if any of query above is failed,  write log.
  
          future plan:
          response callback/change status instead of write_log
  
          """
          pass
function_tokens: def connect ( self , setting : dict ) -> None : pass