python - pip: no module named _internal

Question

I have a problem when I try to use pip in any way. I'm using Ubuntu 16.04.4

I should say that I've used it already, and I never had any problem, but starting today when I use any command I always get the same error (as an example using pip --upgrade).

Traceback (most recent call last):
  File "/usr/local/bin/pip", line 7, in <module>
    from pip._internal import main
ImportError: No module named _internal

I have tried doing sudo apt-get remove python-pip followed by sudo apt-get install python-pip but nothing changed.

Answer 1

This did it for me:

python -m pip install --upgrade pip

Environment: OSX && Python installed via brew