def _nullIf(node):

    '''

    *Must* be run to remove conditions that functions._nullIf() can't handle.

    '''

    params = dict(xml_dom.NodeEntryIter(node))

    null = params.get('null', None)

    value = params.get('value', None)

    if value == None: xml_dom.prune_parent(node) # empty

    elif null == None: xml_dom.replace(node, value) # nothing to null out

simplifying_funcs['_nullIf'] = _nullIf