how to use KX_MouseFocusSensor

How do I use it? there no method to get it, its supposed to be a sub-module of the mouse sensor.

Really nobody knows?!!!

Well, that a game engine related question, gonna move it. So you can ask the right peoples.
[moved]

yeah

How do I use it? there no method to get it,[…]

Here is a method to get it, considering the sensor linked to the controller being a mouse sensor(option “Mouse over”):
Sensor=GameLogic.getCurrentController().getSensor(‘YourSensor’sName’)

To know how to use it, follow this link.