">'a</span>, <span><span class="type-var">'a</span> option</span>)</span> <span class="xref-unresolved">IStdlib</span>.IStd.Container.fold</span> <span class="arrow">&#45;&gt;</span></span>
  <span><span class="label">pp_item</span>:<span>(<span><span class="xref-unresolved">F</span>.formatter <span class="arrow">&#45;&gt;</span></span> <span><span class="type-var">'a</span> <span class="arrow">&#45;&gt;</span></span> unit)</span> <span class="arrow">&#45;&gt;</span></span>
  <span><span class="xref-unresol