utate.html" class="external-link">mutate</a></span><span class="op">(</span></span>
<span>    aggregated <span class="op">=</span> <span class="fu"><a href="../reference/aggregate_pieces_byname.html">aggregate_pieces_byname</a></span><span class="op">(</span><span class="va">mats</span>, piece <span class="op">=</span> <span class="va">pce</span>, margin <span class="op">=</span> <span class="va">mgn</span>, </span>
<span>                                         aggregation_map <span class="op">=</span> <sp