colon at the last line terminates the rule.
          </li>
<li class="listitem">
            The adjacent parts of a sequence should be indented accordingly to have
            all, what belongs to one level, at one indentation level.
          </li>
</ul></div>
<pre class="programlisting"><span class="identifier">program</span>
    <span class="special">=</span>   <span class="identifier">program_heading</span> <span class="special">[</span><span class="identifier">heading_action</span><span class="specia