l-is_error"><a href="#val-is_error" class="anchor"></a><code><span class="keyword">val</span> is_error : <span><span>(<span class="type-var">'a</span>, <span class="type-var">'b</span>)</span> Stdlib.result</span> <span>&#45;&gt;</span> bool</code></dt><dt class="spec value" id="val-note"><a href="#val-note" class="anchor"></a><code><span class="keyword">val</span> note : <span class="type-var">'err</span> <span>&#45;&gt;</span> <span><span class="type-var">'a</span> option</span> <span>&#45;&gt;</span> <s