code: def test_default_types():
      dg = dgl.graph([])
      g = dgl.graph(([], []))
      assert dg.ntypes == g.ntypes
      assert dg.etypes == g.etypes
  
imports: import math
  import numbers
  import backend
  import dgl
  import networkx
  import numpy
  import pytest
  import scipy.sparse
  from dgl import DGLError
label_desc: Use image node_id 16 for calling a global function with example usage: test_default_types() without return types