title: can not import Protocol from typing
body: <p>I have fresh installed Python 3.7-32 on Windows 10.</p>
  
  <p>I want to try Protocols python approach and I do next:</p>
  
  <p>file test_protocols.py with only one row:</p>
  
  <pre><code>from typing import Protocol
  </code></pre>
  
  <p>then:</p>
  
  <pre><code>&gt;python test_protocols.py
  </code></pre>
  
  <p>And I have next error message that is needed to be explained:</p>
  
  <pre><code>Traceback (most recent call last):
    File "test_protocols.py", line 1, in &lt;module&gt; 
      from typing import Protocol
  ImportError: cannot import name 'Protocol' from 'typing' (C:\Programing\Python\Python37-32\lib\typing.py)
  </code></pre>
  
  <p>What do I do wrong?</p>
  
  <p>Maybe I have read PEP-0544 wrong but from my point of view I do the same as it is documented.</p>