def setChild(self,node):
    if node not in self.children:
        self.children.append(node)
        print(node.title + ' >is now a child of< ' + self.title)
    else:
        self.children.remove(node)
        print(node.title + ' >is no longer a child of< ' + self.title)


class A:
    def __init__(self,**kwargs):
        defaults = {
            'title' : 'no title',
            'children' : [],
           'setChild' : setChild
        }
        self.__dict__.update(defaults)
        self.__dict__.update(kwargs)
    def __call__(self,**kwargs):
        return kwargs