(self, node)
return node.is_ancestor(self)
If node is descendent of self
                Get the difference in level
                If not, None
If node is descendent of self
                Get the difference in level
                If not, None
If node is descendent of self Get the difference in level If not None
def is_descendent(self, node):
        """
                If node is descendent of self
                Get the difference in level
                If not, None
        """
        return node.is_ancestor(self)
def is_descendent ( self , node ) : return node . is_ancestor ( self )