def __find_mouse_grabber(self):
if self.__mouse_grabber is None:<EOL><INDENT>return None<EOL><DEDENT>def recursive_find(parent):<EOL><INDENT>grabber = parent.__mouse_grabber<EOL>return parent if grabber is None else recursive_find(grabber)<EOL><DEDENT>return recursive_find(self)<EOL>
Return which of this widget's children or grandchildren is grabbing the 
mouse, or None if none of them are.

If this method returns a widget, all mouse events received by this 
widget will be directed to that widget, regardless of where it is in 
relation to the mouse.  Also note that unless this method is being 
called on the root widget, some widget elsewhere in the hierarchy may 
still be grabbing the mouse even if this returns None.