 subsequent
        adds and deletes to and from the container will not result in
        dangling references (will not crash Python).
      </li>
      <li>
        Support slice indexes.
      </li>
      <li>
        Accept Python container arguments (e.g. lists, tuples) wherever
        appropriate.
      </li>
      <li>
        Allow for extensibility through re-definable policy classes.
      </li>
      <li>
        Provide predefined support for the most common STL and STL like
        indexable co