an> <span class="arrow">&#45;&gt;</span></span> bool)</span> <span class="arrow">&#45;&gt;</span></span>
  <span><span><span class="type-var">'a</span> list</span> <span class="arrow">&#45;&gt;</span></span>
  <span><span><span class="type-var">'a</span> list</span> <span class="arrow">&#45;&gt;</span></span>
  <span><span class="type-var">'a</span> list</span> * <span><span class="type-var">'a</span> list</span> * <span><span class="type-var">'a</span> list</span></span></code></div></div><div class="odoc-