title: Change project interpreter after creation Pycharm
body: <p>I've already changed the default project interpreter in PyCharm under <code>File</code> | <code>Default Settings</code> | <code>Project Interpreter</code> to Python 3.6, but when I try to write variable annotations (e.g. <code>int: x = 6</code>) PyCharm complains that <code>Python version 3.4 does not support variable annotations</code>, as Python 3.4 was the former interpreter I was using.</p>
  
  <p>How do I change the syntax check to that of Python 3.6? Or any other interpreter, for that matter.</p>