matically wraps these
      special Python methods (taken from the Python reference: <a href=
      "http://www.python.org/doc/current/ref/sequence-types.html">Emulating
      container types</a>):
    </p>
    <dl>
      <dd>
        <dl>
          <dt>
            <b><a name="l2h-126"><tt class=
            "method">__len__</tt></a></b>(<var>self</var>)
          </dt>
          <dd>
            Called to implement the built-in function <tt class=
            "function">len()</tt><a name="l2h-134">&nbsp;<