e></pre><div class="info ">
<div class="info-desc">
<p><code class="code">assoc&nbsp;a&nbsp;l</code> returns the value associated with key <code class="code">a</code> in the list of
   pairs <code class="code">l</code>. That is,
   <code class="code">assoc&nbsp;a&nbsp;[&nbsp;...;&nbsp;(a,b);&nbsp;...]&nbsp;=&nbsp;b</code>
   if <code class="code">(a,b)</code> is the leftmost binding of <code class="code">a</code> in list <code class="code">l</code>.
   Raise <code class="code"><span class="constructor">Not_