ass="def-type"><var class="var">out</var> =</code> <strong class="def-name">mergecats</strong> <code class="def-code-arguments">(<var class="var">obj</var>, <var class="var">oldcats</var>, <var class="var">newcat</var>)</code><a class="copiable-link" href="#index-mergecats-1"> &para;</a></span></dt>
<dd>
<p>Merge multiple categories.
</p>
<p>Merges the categories <var class="var">oldcats</var> into a single category. If <var class="var">newcat</var>
is specified, that new category is added if necessary, and