code: def test_data_grad_reference():
      v = nn.Variable([2, 3, 4])
      assert v.d.dtype == np.float32
      assert v.g.dtype == np.float32
  
imports: import pytest
  import numpy
  import nnabla
  from nnabla.testing import assert_allclose
label_desc: Use image node_id 3 for calling a global function with example usage: test_data_grad_reference() without return types