 the kleene? In general, it
          is a <code class="computeroutput"><span class="identifier">std</span><span class="special">::</span><span class="identifier">vector</span><span class="special">&lt;</span><span class="identifier">T</span><span class="special">&gt;</span></code>
          where <code class="computeroutput"><span class="identifier">T</span></code> is the attribute
          of the subject. There is a special case though. If <code class="computeroutput"><span class="identifier">T</span></c