code: def test_works(self):
      embedding = np.array([1.5, 2, 3])
      conn.execute(
          "INSERT INTO items (embedding) VALUES (%s), (NULL)",
          (embedding,),
      )
  
      res = conn.execute("SELECT * FROM items ORDER BY id").fetchall()
      assert np.array_equal(res[0][1], embedding)
      assert res[0][1].dtype == np.float32
      assert res[1][1] is None
  
file_path: pgvector-python/tests/test_psycopg.py
imports: import numpy
  from pgvector.psycopg import register_vector, register_vector_async
  import psycopg
  import pytest
label_desc: Use image node_id 2 for calling the TestPsycopg obj's underlying member method code with example usage: obj.test_works() without return types