def METHOD_NAME(self, node, *args, **kw):
    result = super(RenamingMapping, self).METHOD_NAME(node, *args, **kw)
    renamed_result = {}
    for subnode in node.children:
        subnode_to_name = getattr(subnode, "to_name", subnode.name) or subnode.name
        subnode_value = result.get(subnode.name, subnode.missing)
        if subnode_value is colander.drop or subnode_value is colander.null:
            continue
        else:
            renamed_result[subnode_to_name] = subnode_value
    return renamed_result