Cannot pickle mne.preprocessing.ica.ICA anymore

With the current master (installed via pip install git+https://github.com/mne-tools/mne-python.git#egg=mne), I get an error when pickling an mne.preprocessing.ica.ICA object:

import pickle
import mne


print(mne.__version__)
ica = mne.preprocessing.ICA()
raw = mne.io.read_raw_edf("/Users/clemens/Downloads/testfiles/S001R04.edf", preload=True)
ica.fit(raw)
pickle.loads(pickle.dumps(ica))
# Traceback (most recent call last):
#   File "/Users/clemens/Repositories/mnelab/.venv/lib/python3.7/site-packages/IPython/core/interactiveshell.py", line 3296, in run_code
#     exec(code_obj, self.user_global_ns, self.user_ns)
#   File "<ipython-input-8-a056623ee708>", line 1, in <module>
#     pickle.loads(pickle.dumps(ica))
# TypeError: __new__() missing 1 required positional argument: 'val'

The same code works with the latest released version 0.17.2. I didn’t see any change to the ICA object that might be causing this (but maybe I’m missing something). If indeed nothing changed, could this behavior be due to how pip installs stuff from GitHub (vs. “proper” packages from PyPI)? If so, how can I fix this (I need to pickle because I want to use the multiprocessing module)?

[Teekuningas]

This is expected behavior when defining custom __new__-methods.

You could add something like this to utils/_bunch.py 's NamedInt: def __getnewargs__(obj): return obj._name, int(obj)

[cbrnr]

Thanks @Teekuningas, this solves the problem!