MaybeEncodingError while using the run_combination() method

[echonax07]

While running

train_olmar = algos.OLMAR.run_combination(train, window=5, eps=[3,5,10,15])
train_olmar.plot()

I get the following error

---------------------------------------------------------------------------
MaybeEncodingError                        Traceback (most recent call last)
<ipython-input-53-a58f3354f3e1> in <module>
----> 1 train_olmar = algos.OLMAR.run_combination(train, window=5, eps=[3,5,10,15])
      2 train_olmar.plot()

~/anaconda3/lib/python3.8/site-packages/universal/algo.py in run_combination(cls, S, **kwargs)
    299         # try all combinations in parallel
    300         with tools.mp_pool(n_jobs) as pool:
--> 301             results = pool.map(
    302                 _run_algo_params, [(S, cls, all_params) for all_params in params_to_try]
    303             )

~/anaconda3/lib/python3.8/multiprocessing/pool.py in map(self, func, iterable, chunksize)
    362         in a list that is returned.
    363         '''
--> 364         return self._map_async(func, iterable, mapstar, chunksize).get()
    365 
    366     def starmap(self, func, iterable, chunksize=None):

~/anaconda3/lib/python3.8/multiprocessing/pool.py in get(self, timeout)
    769             return self._value
    770         else:
--> 771             raise self._value
    772 
    773     def _set(self, i, obj):

MaybeEncodingError: Error sending result: '[<universal.result.AlgoResult object at 0x7f62d07f00a0>]'. Reason: 'AttributeError("'NoneType' object has no attribute 'picklable'")'