re><span id="VALcombine"><span class="keyword">val</span> combine</span> : <code class="type">'a list -&gt; 'b list -&gt; ('a * 'b) list</code></pre><div class="info ">
<div class="info-desc">
<p>Transform a pair of lists into a list of pairs:
   <code class="code">combine&nbsp;[a1;&nbsp;...;&nbsp;an]&nbsp;[b1;&nbsp;...;&nbsp;bn]</code> is
   <code class="code">[(a1,b1);&nbsp;...;&nbsp;(an,bn)]</code>.
   Raise <code class="code"><span class="constructor">Invalid_argument</span></code> if the two lists
   h