opy(),
        alternative_a=alternative_a,
        alternative_b=alternative_b,
        selected=selected,
        concat=&#34;_&#34;
    )
    dd = df.groupby([&#34;option_source&#34;, &#34;option_target&#34;])\
        .agg({voter: &#34;count&#34;}).reset_index()

    m = dd.pivot(
        index=&#34;option_source&#34;,
        columns=&#34;option_target&#34;,
        values=voter
    ).fillna(0)

    ids = set(df[&#34;option_source&#34;]) | set(df[&#34;option_target&#34;])
    m = m.reindex(ids)
    m =