def add_child(self, child, name=None, index=None):
self.m1.add_child(child, name, index)<EOL>if index is None:<EOL><INDENT>index = len(self.m2._children)<EOL><DEDENT>self.children_for_m2.append((child, name, index))<EOL>
Add object `child` to the first map and store it for the second.