Can't pickle local object with multi-processing

[darinadaly]

I was able to run the cell with chains=1 but not 4.

with model:
    trace = xo.sample(
        tune=3500,
        draws=3000,
        start=map_soln,
        chains=1,
        initial_accept=0.8,
        target_accept=0.95,
    )

With chains=4, I got AttributeError: Can't pickle local object 'build_model.<locals>.model_lc'
How can I work around this without having to wait a long time with chains=1?

[dfm]

If you're on Mac, this is the relevant issue: pymc-devs/pymc#3844