code: def _assert_is_identical_index(i1, i2):
      assert i1.slice_data() == i2.slice_data()
      assert F.array_equal(i1.tousertensor(), i2.tousertensor())
  
imports: import io
  import pickle
  import unittest
  import backend
  import dgl
  import dgl.function
  import networkx
  import pytest
  import scipy.sparse
  from dgl.graph_index import create_graph_index
  from dgl.utils import toindex
  from utils import assert_is_identical, assert_is_identical_hetero, check_graph_equal, get_cases, parametrize_idtype
label_desc: Use image node_id 4 for calling a global function with example usage: _assert_is_identical_index(i1, i2) without return types