rap">either:<a class="type" title="Either wraps one value of two possible types." href="../thx/Either.html">Either</a>&lt;<span class="type">L</span>, <span class="type">R</span>&gt;</span>):<span class="type">Option</span>&lt;<span class="type">L</span>&gt;</code></p></h3><div class="doc"><p>Converts the Either<L, R> to an Option<L> containing the Left value if Left, or None if Right.</p></div></div><div class="field "><a name="toLeftUnsafe"></a><h3><p><code><span class="label">static</span><a href="#toLef