title: Python Project - ImportError: No module named XXX?
body: <p>I am building a python project, where I have currently 2 modules <code>dr</code> and <code>mg</code>. </p>
  
  <p>I have done <strong>exactly the same thing</strong> to these two modules, but <code>dr</code> can be imported in <code>main.py</code>, whereas <code>mg</code> cannot.</p>
  
  <pre><code>&gt;&gt;&gt; from mg import visualization as vl
  Traceback (most recent call last):
    File "&lt;stdin&gt;", line 1, in &lt;module&gt;
  ImportError: No module named mg
  &gt;&gt;&gt; from dr import simulation as sm
  &gt;&gt;&gt; 
  </code></pre>
  
  <p>I <strong>have added both</strong> <code>dr</code> and <code>mg</code> folders into the <code>PYTHONPATH</code> as seen from the small green plus sign there on the folder names.</p>
  
  <p><img src="https://i.stack.imgur.com/4QeS3.png" alt="enter image description here"></p>
  
  <p>Where goes wrong?</p>