* Initialize _attr_native_value when running
* Fix return type on update_sensor_state()
move init at startup if _attr_native_value is None
* allow update _attr_native_value when running and none
* redo Add sensor
* move back to ClientError
simplify washer_state
* Cleanup Sensor definitions
* Seperated EndTimeSensor
* Clean up WasherDryerTimeClass
* Start with Timestamp = None
* Clean up class description
* One more ClientError
* change to restore sensor
* Don't update when no state change
* Seperate washer tests
Add restore_state test
* Remove unused loop in washer sensor test
* No loops in sensor tests
* Remove unnecessary SensorTestInstance