title: No module named 'pip._internal.cli.main'
body: <p>Pip does not work.
  Error:</p>
  <pre><code>  File &quot;C:\ProgramData\Anaconda3\Scripts\pip-script.py&quot;, line 6, in &lt;module&gt;
      from pip._internal.cli.main import main
  ModuleNotFoundError: No module named 'pip._internal.cli.main' 
  </code></pre>
  <p>None of the solutions of related issues solves it.
  Should I reinstall anaconda and a hundred of site-packages? Is it an only solution?</p>