code: def testMultiMeshWithHostMesh(self, host_to_tpu):
      self.skipForDeviceType(
          ["CPU"],
          "Skipping test as only CPU mesh is available for multi-meshtest.",
      )
  
      sharded_layout_on_tpu = Layout([_MESH_DIM_X], self.second_mesh)
      host_layout = Layout(
          sharded_layout_on_tpu.sharding_specs,
          sharded_layout_on_tpu.mesh.host_mesh(),
      )
  
      if host_to_tpu:
          source_layout = host_layout
          target_layout = sharded_layout_on_tpu
      else:
          source_layout = sharded_layout_on_tpu
          target_layout = host_layout
  
      numpy_a = constant_op.constant([1, 2, 3, 4], dtype=dtypes.int32)
  
      # TODO(b/193443769): switch to a single copy_to_mesh when this is supported.
      replicated_layout = Layout.replicated(
          source_layout.mesh, source_layout.rank
      )
      a = api.copy_to_mesh(numpy_a, replicated_layout)
      a = api.relayout(a, source_layout)
  
      @polymorphic_function.function
      def func(t):
          target_tensor = api.copy_to_mesh(t, target_layout)
          return array_ops.identity(target_tensor)
  
      with ops.device_v2(api.device_name()):
          dtensor_output = func(a)
  
      self.assertDTensorEqual(numpy_a, target_layout, dtensor_output)
  
imports: from absl.testing import parameterized
  import numpy
  from tensorflow.dtensor.python import accelerator_util
  from tensorflow.dtensor.python import api
  from tensorflow.dtensor.python import config
  from tensorflow.dtensor.python import d_variable
  from tensorflow.dtensor.python import layout
  from tensorflow.dtensor.python.tests import test_util
  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 errors_impl
  from tensorflow.python.framework import ops
  from tensorflow.python.ops import array_ops
  from tensorflow.python.ops import gen_math_ops
  from tensorflow.python.ops import math_ops
  from tensorflow.python.platform import test
label_desc: Use image node_id 19 for calling the MultiMeshTest obj's underlying member method code with example usage: obj.testMultiMeshWithHostMesh(host_to_tpu) and returns: array_ops