class="token operator">&gt; </span><a href="-not-empty-set.html"><span class="token function"><strike>NotEmptySet</strike></span></a><span class="token punctuation">(</span><span class="parameters "><span class="parameter ">head<span class="token operator">: </span><a href="-not-empty-set.html">E</a><span class="token punctuation">, </span></span><span class="parameter "><span class="token keyword">vararg </span>tail<span class="token operator">: </span><a href="-not-empty-set.html">E</a></span></span><span