code: def test_batch_keeps_empty_data(idtype):
      g1 = dgl.graph(([], [])).astype(idtype).to(F.ctx())
      g1.ndata["nh"] = F.tensor([])
      g1.edata["eh"] = F.tensor([])
      g2 = dgl.graph(([], [])).astype(idtype).to(F.ctx())
      g2.ndata["nh"] = F.tensor([])
      g2.edata["eh"] = F.tensor([])
      g = dgl.batch([g1, g2])
      assert "nh" in g.ndata
      assert "eh" in g.edata
  
file_path: dgl/tests/python/common/test_batch-graph.py
imports: import unittest
  import backend
  import dgl
  import numpy
  from utils import parametrize_idtype
label_desc: Use image node_id 11 for calling a global function with example usage: test_batch_keeps_empty_data(idtype) without return types