n class="o">.</span><span class="n">where</span><span class="p">(</span><span class="n">idx1</span> <span class="o">!=</span> <span class="n">idx2</span><span class="p">)[</span><span class="mi">0</span><span class="p">]</span>
        <span class="n">idx1</span> <span class="o">=</span> <span class="n">idx1</span><span class="p">[</span><span class="n">idx</span><span class="p">]</span>
        <span class="n">idx2</span> <span class="o">=</span> <span class="n">idx2</span><span class="p">[</span><span cla