title: Unresolved attribute reference 'keys' for class 'dict'
body: <p>Pycharm highlights ".keys()" on line 5 and gives me following warning for it for this illustrative code:</p>
  
  <pre><code>1  def testfunc():
  2      mydic = {}
  3      for x in range(5):
  4          mydic[x] = str(x)
  5      elems = set(mydic.keys())
  </code></pre>
  
  <p>Python Interpretor: python2.7 from anaconda. Pycharm v2017.3</p>
  
  <p>Can someone help me understand why do I get this warning? Everything works as expected. </p>
  
  <p>Screenshots:
  <a href="https://i.stack.imgur.com/XYQmW.png" rel="noreferrer"><img src="https://i.stack.imgur.com/XYQmW.png" alt="enter image description here"></a></p>
  
  <p><a href="https://i.stack.imgur.com/f30HV.png" rel="noreferrer"><img src="https://i.stack.imgur.com/f30HV.png" alt="enter image description here"></a></p>
  
  <p><a href="https://i.stack.imgur.com/WBWjO.png" rel="noreferrer"><img src="https://i.stack.imgur.com/WBWjO.png" alt="enter image description here"></a></p>