an class="mdzsyn-coresym">+</span> <span class="mdzsyn-symbol">x</span> <span class="mdzsyn-symbol">x</span> <span class="mdzsyn-symbol">y</span>)) <span class="mdzsyn-number">10</span> <span class="mdzsyn-number">20</span>)

<span class="mdzsyn-comment"># Will throw an error about the wrong arity</span>
((<span class="mdzsyn-coresym">fn</span> [<span class="mdzsyn-symbol">x</span>] <span class="mdzsyn-symbol">x</span>) <span class="mdzsyn-number">1</span> <span class="mdzsyn-number">2</span>)
<span class="