code: def test_serialize_heterograph_s3():
      path = "s3://dglci-data-test/graph2.bin"
      g_list0 = create_heterographs(F.int64) + create_heterographs(
          F.int32
      )
      dgl.save_graphs(path, g_list0)
  
      g_list = dgl.load_graphs(path, [0, 2, 5])
      assert g_list[0].idtype == F.int64
      # assert g_list[1].restrict_format() == 'csr'
      assert np.allclose(
          F.asnumpy(g_list[1].nodes["user"].data["hh"]), np.ones((4, 5))
      )
      assert np.allclose(
          F.asnumpy(g_list[2].nodes["user"].data["hh"]), np.ones((4, 5))
      )
      edges = g_list[0]["follows"].edges()
      assert np.allclose(F.asnumpy(edges[0]), np.array([0, 1, 2]))
      assert np.allclose(F.asnumpy(edges[1]), np.array([1, 2, 3]))
  
imports: import os
  import tempfile
  import time
  import unittest
  import warnings
  import backend
  import dgl
  import dgl.ndarray
  import numpy
  import pytest
  import scipy
  from dgl.data.utils import load_labels, load_tensors, save_tensors
label_desc: Use image node_id 16 for calling a global function with example usage: test_serialize_heterograph_s3() without return types