pan><span class="co"># S3 method for class 'data.frame'</span></span>
<span><span class="fu">add_topo_sort</span><span class="op">(</span><span class="va">x</span>, outlets <span class="op">=</span> <span class="cn">NULL</span><span class="op">)</span></span>
<span></span>
<span><span class="co"># S3 method for class 'hy'</span></span>
<span><span class="fu">add_topo_sort</span><span class="op">(</span><span class="va">x</span>, outlets <span class="op">=</span> <span class="cn">NULL</span><span class="op">