title: How to import modules in Python framework with multiple subfolder
body: <p>My question might have discussed in earlier posts too, but couldn't get proper answer applicable for my scenario. Hence posting it as a new query.
  I have multiple sub-folders where module tries to import modules present across multiple subfolders.</p>
  <p>Folder Structure:</p>
  <pre><code>main
  |-- lib
  |   |-- lib1.py
  |   |-- lib2.py
  |   `-- lib3.py
  |-- common
  |   |-- lib4.py
  |-- tests
  |   |--folder1
  |       |-- script1.py
  |       |-- folder2
  |           |-- script2.py
  |   |--scriptA.py
  |   `--scriptB.py
  </code></pre>
  <p>Use case/Requirements:</p>
  <ol>
  <li>script1 &amp; script2  import functions from  module lib1.py.</li>
  <li>lib1 wants to import functions from lib2.py &amp; lib3.py</li>
  <li>lib4.py import funtions from lib1 &amp; lib2</li>
  </ol>
  <p>I tried adding blank <code>__init__.py</code> in root folder (main) and the all other subfolders. But couldn't get this working. Ending up with 'ModuleNotFound' error.</p>