importioimportpickleclassZeroCopyByteArray(bytearray):def__reduce_ex__(self,protocol):returntype(self), (pickle.PickleBuffer(self),),Nonedata= [ZeroCopyByteArray(),ZeroCopyByteArray(),]# this worksf=io.BytesIO()pickler=pickle.Pickler(f,protocol=5)pickler.dump(data)# this hits memo assertionf=io.BytesIO()pickler=pickle._Pickler(f,protocol=5)pickler.dump(data)

Traceback (most recent call last):  File"bug.py", line24, in<module>    pickler.dump(data)  File"/pickle.py", line487, indumpself.save(obj)  File"/pickle.py", line560, insave    f(self, obj)# Call unbound method with explicit self^^^^^^^^^^^^  File"/pickle.py", line932, insave_listself._batch_appends(obj)  File"/pickle.py", line956, in_batch_appends    save(x)  File"/pickle.py", line603, insaveself.save_reduce(obj=obj,*rv)  File"/pickle.py", line692, insave_reduce    save(args)  File"/pickle.py", line560, insave    f(self, obj)# Call unbound method with explicit self^^^^^^^^^^^^  File"/pickle.py", line887, insave_tuple    save(element)  File"/pickle.py", line560, insave    f(self, obj)# Call unbound method with explicit self^^^^^^^^^^^^  File"/pickle.py", line842, insave_picklebufferself.save_bytearray(m.tobytes())  File"/pickle.py", line821, insave_bytearrayself.memoize(obj)  File"/pickle.py", line508, inmemoizeassertid(obj)notinself.memo^^^^^^^^^^^^^^^^^^^^^^^^AssertionError