title: Problems in importing self-defined packages and modules?
body: <p>I am using Spyder.</p>
  
  <p>I have just started building a project. Its architecture is currently as shown.</p>
  
  <p><img src="https://i.stack.imgur.com/oMMo2.png" alt="enter image description here"></p>
  
  <p>As shown, I have 2 packages, one of which has a module called <code>trajectorygeneration</code> now.
  Both the <code>__init__.py</code> files are automatically generated. I am trying to import the module into the <code>main.py</code>, but I ended up with such error messages:</p>
  
  <pre><code>&gt;&gt;&gt; from generation import trajectorygeneration
  Traceback (most recent call last):
    File "&lt;stdin&gt;", line 1, in &lt;module&gt;
  ImportError: No module named generation
  </code></pre>
  
  <p><strong>How may I fix this problem?</strong></p>