title: Pylint error with valid code inside class
body: <p>I have set up an reentrant lock (RLock) in a class like so inside the init function:</p>
  
  <pre><code>self.lock= threading.RLock() 
  </code></pre>
  
  <p>If I try to get a count of the locks like so:</p>
  
  <pre><code>self.lock._RLock__count 
  </code></pre>
  
  <p>I get this error with pylint:</p>
  
  <pre><code>E:581,15: Instance of '_RLock' has no '_RLock__count' member (no-member)
  </code></pre>
  
  <p>The code works fine, I only have a problem passing pylint testing, do I have to tell it to ignore this like a dynamic attribute?</p>