 class="mi">0</span><span class="p">]</span>
        <span class="n">z_indices</span> <span class="o">=</span> <span class="n">np</span><span class="o">.</span><span class="n">where</span><span class="p">(</span><span class="n">xyz</span> <span class="o">==</span> <span class="mi">2</span><span class="p">)[</span><span class="mi">0</span><span class="p">]</span>

        <span class="k">if</span> <span class="nb">len</span><span class="p">(</span><span class="n">z_indices</span><span class="p">)</span> <spa