 elements can be removed from the sequence.

            The same exceptions should be raised for improper <var>key</var>

            values as for the <tt class="method">__getitem__()</tt> method.

          </dd>

        </dl>

        <dl>

          <dt>

            <b><a name="l2h-132"><tt class=

            "method">__iter__</tt></a></b>(<var>self</var>)

          </dt>

          <dd>

            This method is called when an iterator is required for a

            container. This m