pan class="token operator">: </span><a href="index.html">E</a><span class="token punctuation">, </span></span><span class="parameter ">tail<span class="token operator">: </span><a href="index.html">E</a></span></span><span class="token punctuation">)</span> : <a href="https://kotlinlang.org/api/latest/jvm/stdlib/kotlin.collections/-abstract-set/index.html">AbstractSet</a><span class="token operator">&lt;</span><span class="token keyword"></span><a href="index.html">E</a><span class="token operator">&gt; </s