        <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 changes to the

            values for keys, or if new keys can be added, or for sequences if

            elements can be replaced. The same exceptions should be raised

            for improper <var>key</var> values as for the <tt class=

            "method">__getitem__()</tt> method.

          <