n class="keyword">module </span><a href="Address">Address</a> : <span class="keyword">sig</span> ... <span class="keyword">end</span></code></div><div class="spec module" id="module-Area"><a href="#module-Area" class="anchor"></a><code><span class="keyword">module </span><a href="Area">Area</a> : <span class="keyword">sig</span> ... <span class="keyword">end</span></code></div><div class="spec module" id="module-Article"><a href="#module-Article" class="anchor"></a><code><span class="keyword">module </span>