code: def testStdNan(self):
      rt_as_list = [[0, 1, 1, 0], [4], [], [5, 6], [7], [8, 9]]
      expected = [
          std(0, 1, 1, 0),
          std(4),
          std(),
          std(5, 6),
          std(7),
          std(8, 9),
      ]
      rt_input = ragged_factory_ops.constant(rt_as_list)
      reduced = ragged_math_ops.reduce_std(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 6 for calling the RaggedReduceOpsTest obj's underlying member method code with example usage: obj.testStdNan() without return types