code: def _device_to_host_funcs():
      """Generates device-to-host transfer functions."""
      if jax.default_backend() == "cpu":
          # device-to-host does not incur transfer on the CPU backend.
          return []
  
      with jax.transfer_guard_host_to_device("allow"):
          device_arrays = [jnp.ones(1) for _ in range(6)]
      return [
          # (function name, is an explicit transfer?, function)
          (
              "device_to_host_jax_device_get",
              True,
              lambda: jax.device_get(device_arrays[0]),
          ),
          (
              "device_to_host_np_asarray",
              False,
              lambda: np.asarray(device_arrays[1]),
          ),
          (
              "device_to_host_copy_to_host_async",
              False,
              lambda: device_arrays[2].copy_to_host_async(),
          ),
          (
              "device_to_host_np_add",
              False,
              lambda: np.add(device_arrays[3], 1),
          ),
          ("device_to_host_str", False, lambda: str(device_arrays[4])),
          (
              "device_to_host_pickle_dumps",
              False,
              lambda: pickle.dumps(device_arrays[5]),
          ),
      ]
  
imports: import contextlib
  import pickle
  from absl.testing import absltest
  from absl.testing import parameterized
  import numpy
  import jax
  import jax._src.test_util
  import jax.numpy
  from jax import config
label_desc: Use image node_id 3 for calling a global function with example usage: _device_to_host_funcs() and returns: list, list