class="keyword">val</span> (*@) : <span><span><span>(<span class="type-var">'a</span>, <span class="type-var">'b</span>)</span> <a href="argument-1-M/index.html#type-t">M.t</a></span> <span class="arrow">&#45;&gt;</span></span> <span><span><span>(<span class="type-var">'a</span>, <span class="type-var">'b</span>)</span> <a href="argument-1-M/index.html#type-t">M.t</a></span> <span class="arrow">&#45;&gt;</span></span> <span><span>(<span class="type-var">'a</span>, <span class="type-var">'b</span>)</span> <a