def _hide_children(self):
for child in self.__yield_all_children():<EOL><INDENT>if child.is_visible:<EOL><INDENT>child._ungrab_mouse()<EOL>child._undraw()<EOL><DEDENT>child.__is_parent_hidden = True<EOL><DEDENT>
Hide all of the widget's children.

This method is part of the process of hiding the widget itself, so it 
is assumed that the widget is hidden when this method is called.