code: def __init__(self, a, b):
      self.astat = ArrayStats(a)
      self.bstat = ArrayStats(b)
      self.diffstat = ArrayStats(a - b)
  
imports: from nnabla.utils import nnabla_pb2
  from six.moves import filter
  import copy
  import nnabla
  import nnabla.ext_utils
  import nnabla.functions
  import nnabla.utils.converter
  import nnabla.dtypes
  from nnabla.testing import assert_allclose
  import numpy
  import numpy
  import platform
label_desc: Use image node_id 1 to create a new ArrayDiffStats object  with example: obj = ArrayDiffStats(a, b)