-opt_to_big_int" class="anchor"></a><code><span><span class="keyword">val</span> opt_to_big_int : <span><span><a href="#type-t">t</a> option</span> <span class="arrow">&#45;&gt;</span></span> <span class="xref-unresolved">Z</span>.t</span></code></div></div><div class="odoc-spec"><div class="spec value anchored" id="val-is_one"><a href="#val-is_one" class="anchor"></a><code><span><span class="keyword">val</span> is_one : <span><a href="#type-t">t</a> <span class="arrow">&#45;&gt;</span></span> bool</span></