 type with elements of any hashable type, or you can easily
create bit masks with <code>SetAlgebra</code> conformance using the <code>OptionSet</code>
protocol. See those types for more information.</p>
<blockquote>
<p>Note:
Unlike ordinary set types, the <code>Element</code> type of an <code>OptionSet</code> is identical to the <code>OptionSet</code> type itself. The <code>SetAlgebra</code> protocol is specifically designed to accommodate both kinds of set.</p>
</blockquote>
<h3>Conforming to the SetAlgebr