def strip(node, preserve=set()):

    '''Replaces every XML function with its last parameter (which is usually its

    value), except for structural functions, which are evaluated by process().

    @param preserve set(str...) XML functions not to remove.

        * container can be any iterable type

    '''

    preserve = set(preserve)

    name = node.tagName

    is_func = is_xml_func_name(name) and name not in preserve

    if is_func and name in structural_funcs: process(node)

    else:

        for child in xml_dom.NodeElemIter(node): strip(child, preserve)

        if is_func:

            value = pop_value(list(xml_dom.NodeTextEntryIter(node)), None)

            xml_dom.replace_with_text(node, value)