n>

<span class="sd">        * Different chains can be assigned for each i and j,</span>
<span class="sd">          if a dictionary that maps from segment (str) to PDB chain (str)</span>
<span class="sd">          is given. In this case, columns &quot;segment_i&quot; and &quot;segment_j&quot;</span>
<span class="sd">          must be present in the pairs dataframe.</span>

<span class="sd">    atom : str, optional (default: &quot;CA&quot;)</span>
<span class="sd">        Put end of line on this atom in each