def _merge_to_base(source_df: pd.DataFrame, target_df: pd.DataFrame): """ """ src_accs = list(source_df.Accession) tgt_accs = list(target_df.Accession) add_row_idxs: List[int] = [] for ii, src in enumerate(src_accs): for jj, tgt in enumerate(tgt_accs): if src & tgt: tgt_accs[jj] = src | tgt break else: add_row_idxs.append(ii) target_df.Accession = tgt_accs if add_row_idxs: target_df = pd.concat([target_df, source_df.iloc[add_row_idxs]], ignore_index=True) return target_df