Slice sampler & n_chains>1: AttributeError: Can't pickle local object 'main.<locals>.logp'

[Gabriel-p]

I'm using the master branch of sampyl. My conda environment:

$ conda list
# packages in environment at /home/gabriel/anaconda3/envs/asteca3:
#
# Name                    Version                   Build  Channel
astropy                   3.0.4            py37h14c3975_0  
atomicwrites              1.1.5                    py37_0  
attrs                     18.1.0                   py37_0  
autograd                  1.2                       <pip>
blas                      1.0                         mkl  
ca-certificates           2018.03.07                    0  
certifi                   2018.8.13                py37_0  
cycler                    0.10.0                   py37_0  
cython                    0.28.5           py37hf484d3e_0  
dbus                      1.13.2               h714fa37_1  
emcee                     2.2.1              pyh24bf2e0_4    astropy
expat                     2.2.5                he0dffb1_0  
fontconfig                2.13.0               h9420a91_0  
freetype                  2.9.1                h8a8886c_0  
future                    0.16.0                    <pip>
glib                      2.56.1               h000015b_0  
gst-plugins-base          1.14.0               hbbd80ab_1  
gstreamer                 1.14.0               hb453b48_1  
icu                       58.2                 h9c2bf20_1  
intel-openmp              2018.0.3                      0  
jpeg                      9b                   h024ee3a_2  
kiwisolver                1.0.1            py37hf484d3e_0  
libedit                   3.1.20170329         h6b74fdf_2  
libffi                    3.2.1                hd88cf55_4  
libgcc-ng                 7.2.0                hdf63c60_3  
libgfortran-ng            7.2.0                hdf63c60_3  
libpng                    1.6.34               hb9fc6fc_0  
libstdcxx-ng              7.2.0                hdf63c60_3  
libuuid                   1.0.3                h1bed415_2  
libxcb                    1.13                 h1bed415_1  
libxml2                   2.9.8                h26e45fe_1  
matplotlib                2.2.2            py37hb69df0a_2  
mkl                       2018.0.3                      1  
mkl_fft                   1.0.4            py37h4414c95_1  
mkl_random                1.0.1            py37h4414c95_1  
more-itertools            4.2.0                    py37_0  
ncurses                   6.1                  hf484d3e_0  
numpy                     1.15.0           py37h1b885b7_0  
numpy-base                1.15.0           py37h3dfced4_0  
openssl                   1.0.2p               h14c3975_0  
pandas                    0.23.3           py37h04863e7_0  
patsy                     0.5.0                    py37_0  
pcre                      8.42                 h439df22_0  
pip                       10.0.1                   py37_0  
pip                       18.0                      <pip>
pluggy                    0.6.0                    py37_0  
psutil                    5.4.6            py37h14c3975_0  
py                        1.5.4                    py37_0  
pyparsing                 2.2.0                    py37_1  
pyqt                      5.9.2            py37h22d08a2_0  
pytest                    3.6.3                    py37_0  
pytest-arraydiff          0.2              py37h39e3cac_0  
pytest-astropy            0.4.0                    py37_0  
pytest-doctestplus        0.1.3                    py37_0  
pytest-openfiles          0.3.0                    py37_0  
pytest-remotedata         0.3.0                    py37_0  
python                    3.7.0                hc3d631a_0  
python-dateutil           2.7.3                    py37_0  
pytz                      2018.5                   py37_0  
qt                        5.9.6                h52aff34_0  
readline                  7.0                  ha6073c6_4  
scipy                     1.1.0            py37hc49cb51_0  
seaborn                   0.9.0                    py37_0  
setuptools                39.2.0                   py37_0  
sip                       4.19.8           py37hf484d3e_0  
six                       1.11.0                   py37_1  
sqlite                    3.24.0               h84994c4_0  
statsmodels               0.9.0            py37h035aef0_0  
tk                        8.6.7                hc745277_3  
tornado                   5.0.2            py37h14c3975_0  
wheel                     0.31.1                   py37_0  
xz                        5.2.4                h14c3975_4  
zlib                      1.2.11               ha838bed_2  

I get a AttributeError: Can't pickle local object 'main.<locals>.logp' in the line

sampyl/sampyl/parallel.py

Line 49 in fb05a0d

new_chains = pool.map(func, samplers)

whenever I use more than one chain and the Slice sampler.