title: Python: Standard way to denote return and parameter types
body: <p>Is there a standard, Pythonic way to express the parameter type and return type of a function?</p>
  
  <p>I am looking for a notation that is:</p>
  
  <ul>
  <li>Recognisable by <code>help()</code></li>
  <li>Recognisable by IDEs</li>
  <li>(Preferrably) described in a PEP</li>
  </ul>
  
  <p>I have seen some examples, like <a href="https://stackoverflow.com/a/5339352/51197">this reSt syntax</a>:</p>
  
  <pre><code>"""replaces template place holder with values
  
  :param timestamp: formatted date to display
  :type timestamp: str or unicode
  :param priority: priority number
  :type priority: str or unicode
  :param priority_name: priority name
  :type priority_name: str or unicode
  :param message: message to display
  :type message: str or unicode
  :returns: formatted string
  :rtype: str or unicode
  """
  </code></pre>
  
  <p>However, I am not sure how official / supported is this format.</p>