code: def query(sql, args=None, many=None, as_dict=False, key='default'):
      
      database = choice(__db[key + '.slave'])
      return database.query(sql, args, many, as_dict)
docs: The connection raw sql query,  when select table,  show table
          to fetch records, it is compatible the dbi execute method::
  
  
      :param sql string: the sql stamtement like 'select * from %s'
      :param args  list: Wen set None, will use dbi execute(sql), else
          dbi execute(sql, args), the args keep the original rules, it shuld be tuple or list of list
      :param many  int: when set, the query method will return genarate an iterate
      :param as_dict bool: when is True, the type of row will be dict, otherwise is tuple
      :param key: a key for your dabtabase you wanna use