title: Does PIP/Python support multiple versions of the same package?
body: <p>Let's say I have a package <code>foo</code>, and <code>foo</code> packages up binary shared objects that I use in multiple Python scripts.</p>
  
  <ul>
  <li>Foo v1 (shared objects)
  
  <ul>
  <li>Bar v1 (requires Foo v1)</li>
  <li>Baz v1 (requires Foo v1)</li>
  </ul></li>
  </ul>
  
  <p>Now I want to push out a new breaking update to Foo.</p>
  
  <ul>
  <li>Foo v2 (shared objects)
  
  <ul>
  <li>Bar v2 (requires Foo v2)</li>
  </ul></li>
  <li>Foo v1 (shared objects)
  
  <ul>
  <li>Bar v1 (requires Foo v1)</li>
  <li>Baz v1 (requires Foo v1)</li>
  </ul></li>
  </ul>
  
  <p>Can old-dependencies with different major versions in semvar be distributed over PyPI? If so, how?</p>