title: Python - add PYTHONPATH during command line module run
body: <p>I want to run:</p>
  
  <pre><code>python somescript.py somecommand
  </code></pre>
  
  <p>But, when I run this I need <code>PYTHONPATH</code> to include a certain directory. I can't just add it to my environment variables because the directory I want to add changes based on what project I'm running. Is there a way to alter <code>PYTHONPATH</code> while running a script? Note: I don't even have a <code>PYTHONPATH</code> variable, so I don't need to worry about appending to it vs overriding it during running of this script.</p>