n class="p">(</span><span class="mi">1</span><span class="p">,</span><span class="nb">len</span><span class="p">(</span><span class="n">coor</span><span class="p">)</span><span class="o">-</span><span class="n">N_chr_beads</span><span class="o">+</span><span class="mi">1</span><span class="p">):</span>
        <span class="n">idx_curr</span> <span class="o">=</span> <span class="n">N_chr_beads</span><span class="o">+</span><span class="n">k</span>
        <span class="n">mol_curr</span> <span class="o">=</s