title: Unable to import class from one app into another in django
body: <p>I am trying to import a class from one Django app inside another Django app.</p>
  
  <pre><code>mainProjectFolder
  |--__init__.py
  |--manage.py
  |--app1
      |--__init__.py
      |--class1.py
  |--app2
      |--__init__.py
      |--anotherClass.py
  |--mainProjectFolder
      |--__init__.py
      |--settings.py
      ...
  </code></pre>
  
  <p>in <code>app2.anotherClass.py</code>, I am doing:</p>
  
  <pre><code>from mainProjectFolder.app1.class1 import Class1
  </code></pre>
  
  <p>And I get the following error: </p>
  
  <pre><code>ImportError: No module named 'mainProjectFolder.app1'
  </code></pre>
  
  <p>I have registered my the apps in <code>INSTALLED_APPS</code> in the <code>settings.py</code> file as well.</p>
  
  <p>Please let me know if anything is unclear, I will edit the required.</p>