ChannelT<span class="special">,</span> <span class="keyword">typename</span> SeverityT<span class="special">&gt;</span> 
  <span class="identifier">channel_severity_filter_actor</span><span class="special">&lt;</span> <span class="identifier">ChannelT</span><span class="special">,</span> <span class="identifier">SeverityT</span> <span class="special">&gt;</span> 
  <span class="identifier">channel_severity_filter</span><span class="special">(</span><span class="identifier">attribute_name</span> <span class=