code: def _chi2(self, expected, actual):
      actual = np.asarray(actual)
      expected = np.asarray(expected)
      diff = actual - expected
      chi2 = np.sum(diff * diff / expected, axis=0)
      return chi2
  
imports: import collections
  import timeit
  import numpy
  from tensorflow.core.protobuf import config_pb2
  from tensorflow.python.client import session
  from tensorflow.python.eager import context
  from tensorflow.python.framework import constant_op
  from tensorflow.python.framework import dtypes
  from tensorflow.python.framework import random_seed
  from tensorflow.python.framework import tensor_shape
  from tensorflow.python.framework import test_util
  from tensorflow.python.ops import array_ops
  from tensorflow.python.ops import control_flow_ops
  from tensorflow.python.ops import math_ops
  from tensorflow.python.ops import random_ops
  from tensorflow.python.platform import test
label_desc: Use image node_id 13 for calling the MultinomialTest obj's underlying member method code with example usage: obj._chi2(expected, actual) and returns: chi2