an>                 margin <span class="op">=</span> <span class="fl">2</span><span class="op">)</span></span>
<span><span class="co">#&gt;       Beatles</span></span>
<span><span class="co">#&gt; duck       10</span></span>
<span><span class="co">#&gt; duck       26</span></span>
<span><span class="co">#&gt; goose      42</span></span></code></pre></div>
<p><code>aggregation_map</code> can use regular expressions to identify
rows and columns to aggregate. Use <code>pattern_type = "literal"</code>
for this 