c</span> <a href="../argument-1-M/index.html#type-t">M.t</a></span>)</span> <span>&#45;&gt;</span> <span><span class="type-var">'a</span> <a href="../argument-1-M/index.html#type-t">M.t</a></span> <span>&#45;&gt;</span> bool</code></dt><dt class="spec value" id="val-identity"><a href="#val-identity" class="anchor"></a><code><span class="keyword">val</span> identity : <span>(<span class="type-var">'a</span> <span>&#45;&gt;</span> <span><span class="type-var">'b</span> <a href="../argument-1-M/index.html#type