><span class="special">&gt;,</span>
      <span class="identifier">policies</span><span class="special">::</span><span class="identifier">discrete_quantile</span><span class="special">&lt;&gt;,</span>
      <span class="identifier">policies</span><span class="special">::</span><span class="identifier">assert_undefined</span><span class="special">&lt;&gt;</span> <span class="special">&gt;::</span><span class="identifier">type</span> <span class="identifier">forwarding_policy</span><span class="special">;</sp