def pg_hnsw_multiple(db_hnsw: None) -> Generator[List[PGVectorStore], None, None]:
    """
    This creates multiple instances of PGVectorStore.
    """
    pgs = []
    for _ in range(2):
        pg = PGVectorStore.from_params(
            **PARAMS,  # type: ignore
            database=TEST_DB_HNSW,
            table_name=TEST_TABLE_NAME,
            schema_name=TEST_SCHEMA_NAME,
            embed_dim=TEST_EMBED_DIM,
            hnsw_kwargs={
                "hnsw_m": 16,
                "hnsw_ef_construction": 64,
                "hnsw_ef_search": 40,
            },
        )
        pgs.append(pg)

    yield pgs

    for pg in pgs:
        asyncio.run(pg.close())

    This creates multiple instances of PGVectorStore.
    
llama-index-integrations/vector_stores/llama-index-vector-stores-postgres/tests/test_postgres.py