def METHOD_NAME(self, iterable):
    """
    Return a new PSet with elements in iterable added
    >>> s1 = s(1, 2)
    >>> s1.update([3, 4, 4])
    pset([1, 2, 3, 4])
    """
    e = self.evolver()
    for element in iterable:
        e.add(element)
    return e.persistent()