title: Why does PyCharm not recognize errors in the main.py file?
body: <p>I am woking on a Kivy application usign PyCharm, but the problem is that in the <code>main.py</code> file, modules, variables that are undefined are not marked as errors.
  <a href="https://i.stack.imgur.com/Em1JY.png" rel="nofollow noreferrer"><img src="https://i.stack.imgur.com/Em1JY.png" alt="enter image description here"></a></p>
  
  <p>At the beginning I thought it was a general problem, but I have tried on different files which name is not <code>main.py</code>, and this is working properly.
  This is happening only in the <code>main.py</code></p>
  
  <p>How can I solve this? Is it maybe a bug of PyCharm?</p>
  
  <p>I am using PyCharm Professional 2016.3.</p>