code: def _nan_equal(a, b):
      try:
          np.testing.assert_equal(a, b)
      except AssertionError:
          return False
      return True
  
imports: import functools
  import operator
  import numpy
  import scipy.sparse
  import pytest
  from ....config import option_context
  from ....session import execute, fetch
  from ....tests.core import require_cupy
  from ....utils import ignore_warning
  from ...datasource import ones, tensor, zeros, arange
  from ..None import add, cos, truediv, frexp, modf, clip, isclose, arctan2, tree_add, tree_multiply
label_desc: Use image node_id 1 for calling a global function with example usage: _nan_equal(a, b) and returns: True, False