Ivan Gromov

Implement itertools.accumulate.__reduce__ and __setstate__

3

Add accumulate.__reduce__ implementation for #3611. Publishing as a draft to collect initial feedback. Behaviour seems to be identical to CPython's, but I'm still testing. # Relevant links - https://github.com/python/cpython/blob/main/Modules/itertoolsmodule.c#L3858-L3894