def METHOD_NAME(tmp_path, lognormed_test_data):
    temp_h5mu = tmp_path / "lognormed_batch.h5mu"
    rna_mod = lognormed_test_data.mod['rna']
    rna_mod.obs['batch'] = 'A'
    column_index = rna_mod.obs.columns.get_indexer(['batch'])
    rna_mod.obs.iloc[slice(rna_mod.n_obs//2, None), column_index] = 'B'
    lognormed_test_data.write_h5mu(temp_h5mu)
    return temp_h5mu