n><span class="nb">len</span><span class="p">(</span><span class="n">transaction</span><span class="p">)):</span>
                    <span class="n">item</span> <span class="o">=</span> <span class="n">key</span><span class="p">[</span><span class="n">i</span><span class="p">]</span>
                    <span class="k">if</span> <span class="n">item</span> <span class="ow">not</span> <span class="ow">in</span> <span class="n">subtree</span><span class="p">:</span>
                        <span class="n">su