"idea">var collection: NotEmptyCollection&lt;Int&gt; = notEmptyListOf(1, 2, 3)<br>var result: NotEmptyCollection&lt;Int&gt;? = collection.tail<br>println(result) // [2, 3]<br><br>collection = notEmptyListOf(-1)<br>result = collection.tail<br>println(result) // null</code></pre><span class="top-right-position"><span class="copy-icon"></span><div class="copy-popup-wrapper popup-to-left"><span class="copy-popup-icon"></span><span>Content copied to clipboard</span></div></span></div></div></div>
</div>
      <d