ImportError: libSM.so.6: impossibile aprire un file oggetto condiviso: Nessun file o directory di questo tipo

OS: Ubuntu 18.04.

Errore:

ImportError                               Traceback (most recent call last)
 in 
     10 from sklearn.model_selection import train_test_split
     11 
---> 12 import cv2
     13 
     14 import matplotlib.pyplot as plt
/usr/local/lib/python3.6/dist-packages/cv2/__init__.py in 
      1 import importlib
      2 
----> 3 from .cv2 import *
      4 from .data import *
      5 
ImportError: libSM.so.6: cannot open shared object file: No such file or directory

Come risolvere

sudo apt-get update

sudo apt-get install -y libsm6 libxext6 libxrender-dev

pip3 install opencv-python