def __init__(self):
self._default_devices = ["<STR_LIT>"]<EOL>self._default_drivers = [("<STR_LIT>",None)]<EOL>self._local_driver = True<EOL>
@note: maybe override variables
    _default_devices -> list type; to genrate tracer map, format is `{device_id: tracer_obj}`
                    e.g.
                         default {"":tracer_obj} use to generate report for local host; 
                         {"192.168.0.1:5555":tracer_obj1, "192.168.0.2:5555":tracer_obj2} use to generate report for remote host if run with mutilple process                                
    _default_drivers -> list type; to define driver map, format is `(device_id: driver)`
                    e.g.
                        default ("", None) use to run case with a driver;
                        [("192.168.0.1:5555":selenium_driver), ("192.168.0.2:5555":appium_driver), ...] use for multiple process to run case with specified drivers