/span>)</span> <span class="xref-unresolved">IStdlib</span>.IStd.Container.fold</span> <span class="arrow">&#45;&gt;</span></span>
  <span><span class="type-var">'t</span> <span class="arrow">&#45;&gt;</span></span>
  <span><span class="type-var">'a</span> <a href="#type-singleton_or_more">singleton_or_more</a></span></span></code></div></div><div class="odoc-spec"><div class="spec value anchored" id="val-mem_nth"><a href="#val-mem_nth" class="anchor"></a><code><span><span class="keyword">val</span> mem_nth