elf) -> Self</a> <span class="required">Required</span><div class="comment collapse in" id="comment-symmetricDifference-6d93d25cdc494974245a2f9a6a777c1c"><p>Returns a new set with the elements that are either in this set or in the
given set, but not in both.</p>
<p>In the following example, the <code>eitherNeighborsOrEmployees</code> set is made up
of the elements of the <code>employees</code> and <code>neighbors</code> sets that are not in
both <code>employees</code> <em>and</em> <code>neighbors</code>. In