code: def testVarianceNan(self):
      rt_as_list = [[0, 1, 2, 3], [4], [], [5, 6], [7], [8, 9]]
      expected = [
          variance(0, 1, 2, 3),
          variance(4),
          variance(),
          variance(5, 6),
          variance(7),
          variance(8, 9),
      ]
      rt_input = ragged_factory_ops.constant(rt_as_list)
      reduced = ragged_math_ops.reduce_variance(rt_input, axis=1)
      self.assertEqualWithNan(self.evaluate(reduced), expected)
  
imports: from absl.testing import parameterized
  import numpy
  from tensorflow.python.eager import context
  from tensorflow.python.framework import constant_op
  from tensorflow.python.framework import dtypes
  from tensorflow.python.framework import test_util
  from tensorflow.python.ops import array_ops
  from tensorflow.python.ops.ragged import ragged_factory_ops
  from tensorflow.python.ops.ragged import ragged_math_ops
  from tensorflow.python.platform import googletest
label_desc: Use image node_id 5 for calling the RaggedReduceOpsTest obj's underlying member method code with example usage: obj.testVarianceNan() without return types