code: def testRFFT(self, num_batch_dim, rfft_op, num_nonbatch_dim, dtype):
      self.skipForDeviceType(
          ["GPU"], "RFFT has numerical issues on GPU"
      )
      shape = [4 for i in range(num_batch_dim + num_nonbatch_dim)]
      np.random.seed(123)
      x = constant_op.constant(
          np.random.normal(0.0, 1.0, np.prod(shape)).reshape(shape),
          dtype=dtype,
      )
      expected_result = rfft_op(
          input=x, fft_length=[2] * num_nonbatch_dim
      )
  
      if num_batch_dim == 0:
          layout_spec = []
      elif num_batch_dim == 1:
          layout_spec = [self._mesh_dim_b]
      elif num_batch_dim == 2:
          layout_spec = [self._mesh_dim_b, self._mesh_dim_x]
      layout = Layout(
          layout_spec + ["unsharded"] * num_nonbatch_dim, self.mesh
      )
  
      x = numpy_util.pack_numpy(x, layout)
      got = rfft_op(input=x, fft_length=[2] * num_nonbatch_dim)
      self.assertDTensorEqual(expected_result, layout, got)
  
imports: import itertools
  from absl.testing import parameterized
  import numpy
  from tensorflow.dtensor.python import api
  from tensorflow.dtensor.python import layout
  from tensorflow.dtensor.python import numpy_util
  from tensorflow.dtensor.python.tests import test_util
  from tensorflow.dtensor.python.tests import test_util_ops
  from tensorflow.python.eager import backprop
  from tensorflow.python.eager import context
  from tensorflow.python.eager.polymorphic_function import polymorphic_function
  from tensorflow.python.framework import constant_op
  from tensorflow.python.framework import dtypes
  from tensorflow.python.framework import ops
  from tensorflow.python.ops import array_ops
  from tensorflow.python.ops import gen_array_ops
  from tensorflow.python.ops import gen_image_ops
  from tensorflow.python.ops import gen_linalg_ops
  from tensorflow.python.ops import nn_impl
  from tensorflow.python.ops import nn_ops
  from tensorflow.python.platform import test
label_desc: Use image node_id 4 for calling the DTensorBatchParallelSPMDTest obj's underlying member method code with example usage: obj.testRFFT(num_batch_dim, rfft_op, num_nonbatch_dim, dtype) without return types