title: Python 'return not' statement in subprocess returncode
body: <p>I just came across a very strange line of code in Python:</p>
  
  <pre><code>....
  self.myReturnCode = externalProcessPopen.returncode
  ....
  ....
  return not self.myReturnCode
  ....
  </code></pre>
  
  <p>What exactly <code>return not</code> stands for? I am aware that the returncode of a Popen process is None while it's still running and a random number once it completes and exits successfully. But what exactly is the author of the code trying to achieve here?</p>
  
  <p>It might also be worth noting that the same author later on checks the return code like this:</p>
  
  <pre><code>if not testClass.testFunction():
      logger.error('Failed to execute Function')
      ....
  </code></pre>