 key</var>)
          </dt>
          <dd>
            Called to implement deletion of
            <code><var>self</var>[<var>key</var>]</code>. Same note as for
            <tt class="method">__getitem__()</tt>. This should only be
            implemented for mappings if the objects support removal of keys,
            or for sequences if 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">_