an class="arrow">&#45;&gt;</span></span> <span><span class="type-var">'a</span> option</span> * <span><span class="type-var">'a</span> <a href="#type-t">t</a></span></span></code></div><div class="spec-doc"><p>Find the value bound to the given key if there is one, or otherwise add a binding for the given key and value.</p></div></div><div class="odoc-spec"><div class="spec value anchored" id="val-find_or_add_lazy"><a href="#val-find_or_add_lazy" class="anchor"></a><code><span><span class="keyword">val</span