class="arrow">&#45;&gt;</span></span>
  <span><span>(<a href="#type-key">key</a> * <span class="type-var">'a</span>)</span> <a href="../../../IStdlib/IContainer/index.html#type-singleton_or_more">IStdlib.IContainer.singleton_or_more</a></span></span></code></div></div><div class="odoc-spec"><div class="spec value" id="val-pp_key" class="anchored"><a href="#val-pp_key" class="anchor"></a><code><span><span class="keyword">val</span> pp_key : <span><a href="../../../IStdlib/PrettyPrintable/index.html">IStdlib.