title: Proper way to relative import in Python 2.7
body: <p>I have a Flask I am migrating from <code>Python3</code> to <code>Python2.7</code>.</p>
  
  <p>My project structure is as follows:</p>
  
  <pre><code>app/
      model/
          __init__.py
          exercise.py
      utils/
          __init__.py
          loader.py
  </code></pre>
  
  <p>The <code>exercise.py</code> class contains the class <code>Exercise</code>. I need to use this in the <code>loader.py</code> file. </p>
  
  <p>The <code>app</code> folder itself is at the top level of a Heroku project, which has a <code>run.py</code> file, which calls the <code>Loader</code> class from <code>loader.py</code>. </p>
  
  <p>Previously I had:</p>
  
  <pre><code>from app.model.exercise import Exercise
  </code></pre>
  
  <p>but this does not work in Python2.7. </p>
  
  <p>Appending to <code>sys.path</code> does not seem to work either.</p>
  
  <p>What is the correct way to do this? </p>