Ubuntu 18.10 ,python 3.6.7, apt-get python3-pip, and then pip -V, ImportError: cannot import name ‘sysconfig’,why?

pip3 -V Traceback (most recent call last): File “/usr/bin/pip3”, line 9, in from pip import main File “/usr/lib/python3/dist-packages/pip/init.py”, line 14, in from pip.utils import get_installed_distributions, get_prog File “/usr/lib/python3/dist-packages/pip/utils/init.py”, line 23, in from pip.locations import ( File “/usr/lib/python3/dist-packages/pip/locations.py”, line 9, in from distutils import sysconfig ImportError: cannot import name ‘sysconfig’