title: open function python not working in __main__.py
body: <p>I would like to use the <code>__main__.py</code> file to run code from. Only the code won't <code>open()</code> files in de dir.
  I used a <code>core.py</code> file that did work with the following code:</p>
  
  <pre><code>with open("data/netlist.txt") as f:
      self.list = f.read()
  </code></pre>
  
  <p>In the new main file the error is:</p>
  
  <pre><code>with open("data/netlist.txt") as f: 
  FileNotFoundError: [Errno 2] No such file or directory: 'data/netlist.txt'
  </code></pre>
  
  <p>The folder looks like this:</p>
  
  <p><a href="https://i.stack.imgur.com/8EctX.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/8EctX.png" alt="The folder looks like this"></a></p>