lass="char">'('</span></code>
          and <code class="computeroutput"><span class="string">", "</span></code>) do <span class="emphasis"><em>not</em></span>
          expose any attribute (well actually, they do expose the special type <code class="computeroutput"><span class="identifier">unused_type</span></code>, but in this context <code class="computeroutput"><span class="identifier">unused_type</span></code> is interpreted as if the
          component does not expose any attribute at all). It is ve