'Relabel the alias values of any children. \'change_map\' is a dictionary
mapping old (current) alias values to the new values.'

def relabel_aliases(self, change_map):

    for (pos, child) in enumerate(self.children):
        if hasattr(child, 'relabel_aliases'):
            child.relabel_aliases(change_map)
        elif hasattr(child, 'relabeled_clone'):
            self.children[pos] = child.relabeled_clone(change_map)
