def immnodeset_union(iterable, *args):
 set = mutnodeset_union(iterable)
 return immnodeset(set, *args)

def immnodeset_union ( iterable , * args ) : set = mutnodeset_union ( iterable ) return immnodeset ( set , * args )
return an immmutable nodeset which is the union of all nodesets in iterable .