title: Add directory to Python path in PyCharm?
body: <p>I want to be able to use the <code>paraview.simple</code> library in PyCharm. I already have paraview installed in my computer. This package cannot be installed with <code>pip</code> and there are no .whl files as far as I can tell. The website <a href="https://www.paraview.org/ParaView/Doc/Nightly/www/py-doc/quick-start.html" rel="noreferrer">docs</a> recommend that the directory containing all the python files be added to PYTHONPATH.</p>
  
  <p>How do I add the relevant folder in PYTHONPATH on my PyCharm session, and keep it there by default, such that when I close out and reopen the <code>paraview.simple</code> library is still available?</p>