nc formUnion(_ other: Self)</a> <span class="required">Required</span><div class="comment collapse in" id="comment-formUnion-9e412b159206685203d2312146d59c60"><p>Adds the elements of the given set to the set.</p>
<p>In the following example, the elements of the <code>visitors</code> set are added to
the <code>attendees</code> set:</p>
<pre><code class="language-swift">var attendees: Set = [&quot;Alicia&quot;, &quot;Bethany&quot;, &quot;Diana&quot;]
let visitors: Set = [&quot;Diana&quot;, &quot;Marcia&quot;,