code: def test_empty_data_initialized():
      g = dgl.graph([])
      g = g.to(F.ctx())
      g.ndata["ha"] = F.tensor([])
      g.add_nodes(1, {"hb": F.tensor([1])})
      assert "ha" in g.ndata
      assert len(g.ndata["ha"]) == 1
  
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 14 for calling a global function with example usage: test_empty_data_initialized() without return types