title: How to import a file in the ROOT folder from a file in a subfolder?
body: <p>I'm working with Python 3.8 and I have a project tree as:</p>
  <pre><code>project folder/
  |__OuterFile.py
  |__folder1/
      |__ folder2/
          |__ folder3/
              |__ InnerFile.py
  </code></pre>
  <p>How could I import OuterFile.py, in the project folder (root folder), from inside InnerFile.py?</p>
  <p>I tried to:</p>
  <ul>
  <li>add <code>__init__.py</code> in <code>/project_folder/</code> and in each subfolder;</li>
  <li>and add the import line <code>from .... import OuterFile</code> in <code>InputFile.py</code>
  but it gives me the error: <code>ImportError: attempted relative import with no known parent package</code></li>
  </ul>