Method __reduce_ex__

Lib/test/pickletester.py:4262–4263

(self, proto)

    def __init__(self, reduce_ex=None):
        self.reduce_ex = reduce_ex
    def __reduce_ex__(self, proto):
        return self.reduce_ex

class REX_one(object):
    """No __reduce_ex__ here, but inheriting it from object"""