al">,</span> <span class="identifier">fallback_to_none</span><span class="special">,</span> <span class="identifier">fallback_to_none</span><span class="special">,</span> <span class="identifier">less</span><span class="special">,</span> <span class="identifier">SeverityCompareT</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="keyword">const</span> <span class="special"