nctions when one wants to build a list.</p><div class="odoc-spec"><div class="spec value anchored" id="val-map_argument"><a href="#val-map_argument" class="anchor"></a><code><span><span class="keyword">val</span> map_argument : 
  <span><span><a href="#type-t">t</a> option</span> <span class="arrow">&#45;&gt;</span></span>
  <span>int <span class="arrow">&#45;&gt;</span></span>
  <span><a href="../FieldPath/index.html#type-t">FieldPath.t</a> <span class="arrow">&#45;&gt;</span></span>
  <span><span class="l