lass="kind">def</span></span> <span class="symbol"><span class="name">on</span><span class="tparams">[<span name="U">U</span>]</span><span class="params">(<span name="f">f: (<span name="scala.math.Ordering.on.U" class="extype">U</span>) =&gt; <a href="HeapHistogramEntry.html" name="com.workday.warp.heaphistogram.HeapHistogramEntry" id="com.workday.warp.heaphistogram.HeapHistogramEntry" class="extype">HeapHistogramEntry</a></span>)</span><span class="result">: <span name="scala.math.Ordering" class="extype">