cannot dump_session with dill in spyder 3.3.3. and python 3

[masteruve]

First of all, I want to congratulate you mmckearns because of the great work behind dill.

I have found the following errors using dill dump_session on spyder ide, or through it's IPython console. In particular i'm on win7, 64x, spyder 3.3.3. on winpython dist and have pre-imported numpy and matplotlib.

First I've tried the normal usage,
dill.dump_session('chk.pkl')

and I've found the following error message:
picle.PicklingError: Can't pickle <class 'matplotlib.axes._subplots.AxesSubplot'>: it's not found as matplotlib.axes._subplots.AxesSubplot

then I've tried following specifications in another thread:
dill.dump_session('chk.pkl', byref=True)
*** TypeError: no defaoult __reduce__ due to non-trivial __cinit__

After reading in another interesting response from you, one possible cause is cython, but i didn't imported it. My imports are:

from selenium import webdriver
from selenium.webdriver.support import expected_conditions as EC
from selenium.webdriver.common.keys import Keys

import random as rd
import pickle as pk
import os, inspect, time
import csv, re

Thank you very much in advance. I hope I can use dill in this context, bc I find the purpose of dill really useful. Regards.