Fatal Python error: PyThreadState_Get

I fail to execute: python -c "import opensim"

the error I get is :
Fatal Python error: PyThreadState_Get: no current thread

Abort trap: 6

my conda list is:

# packages in environment at /Users/vittorio/opt/anaconda3/envs/opensim-rl:
#
# Name                    Version                   Build  Channel
ca-certificates           2019.11.27                    0  
certifi                   2019.11.28               py36_0  
cloudpickle               1.2.2                    pypi_0    pypi
curl                      7.55.1               h2e228d0_4  
cycler                    0.10.0                   pypi_0    pypi
expat                     2.2.6                h0a44026_0  
future                    0.18.2                   pypi_0    pypi
git                       2.15.0          pl526h6165b5f_0  
gym                       0.15.4                   pypi_0    pypi
kiwisolver                1.1.0                    pypi_0    pypi
lapack                    3.6.1                ha44fe06_2    conda-forge
libcxx                    4.0.1                hcfea43d_1  
libcxxabi                 4.0.1                hcfea43d_1  
libedit                   3.1.20181209         hb402a30_0  
libffi                    3.2.1                h475c297_4  
libgfortran               3.0.1                h93005f0_2  
libiconv                  1.15              h01d97ff_1005    conda-forge
libssh2                   1.8.0                h322a93b_4  
matplotlib                3.1.2                    pypi_0    pypi
ncurses                   6.1                  h0a44026_1  
numpy                     1.18.1                   pypi_0    pypi
openblas                  0.2.19                        0    kidzik
opencv-python             4.1.2.30                 pypi_0    pypi
opensim                   4.0.0                   py36_17    kidzik
openssl                   1.0.2u               h1de35cc_0  
osim-rl                   3.0.11                   pypi_0    pypi
pcre                      8.43                 h0a44026_0  
perl                      5.26.2            haec8ef5_1006    conda-forge
pip                       19.3.1                   py36_0  
pyglet                    1.3.2                    pypi_0    pypi
pyparsing                 2.4.6                    pypi_0    pypi
python                    3.6.4                hc167b69_3  
python-dateutil           2.8.1                    pypi_0    pypi
readline                  7.0                  h1de35cc_5  
redis                     3.3.11                   pypi_0    pypi
scipy                     1.4.1                    pypi_0    pypi
setuptools                44.0.0                   py36_0  
six                       1.13.0                   pypi_0    pypi
sqlite                    3.30.1               ha441bb4_0  
timeout-decorator         0.4.1                    pypi_0    pypi
tk                        8.6.8                ha441bb4_0  
wheel                     0.33.6                   py36_0  
xz                        5.2.4                h1de35cc_4  
zlib                      1.2.11               h1de35cc_3  

any help would be much appreciated :slight_smile: