title: Proper way to type hint a private property in python
body: <p>Following PEP 526 I'm wondering how to properly type hint an instance or class attribute that is decorated by a property. Do I type hint the underlying attribute or the name or the property?</p>
  
  <p>Example of typing the attribute:</p>
  
  <pre><code>class Sample(object):
      _target_dir: Path
  
      @property
      def target_dir(self):
          pass
  </code></pre>
  
  <p>Or typing the property:</p>
  
  <pre><code>class Sample(object):
      target_dir: Path
  </code></pre>
  
  <p>Or some other way? Is it the same for instance and class variables?</p>