Not really well versed with python/sql joins in general, but it looks like this inner join is producing 2 identical columns of my_id, mod_id which have identical values?

  df = (
    lhs_df[LHS_COLS]
    .merge(
      rhs_df, left_on="my_id", right_on="mod_id", suffixes=("_lhs", "_rhs"), how="inner"
    )
    .merge(final_df[COLS], on="my_id", how="left")
    .rename(
      columns={
        "my_id": "id_fixed",
        "mod_id": "id_mod",
      }
    )
  )

I don't understand what the point of this is instead of dropping one of the columns and have downstream consumers that used id_mod use id_fixed instead. Am I misunderstanding how the inner join here works?