code: def test_nesting(self):
      with jax.transfer_guard("disallow"):
          with jax.transfer_guard("allow"):
              with self.assertAllows("host_to_device_jnp_ones"):
                  jnp.ones(1)
          with self.assertDisallows("host_to_device_jnp_ones"):
              jnp.ones(1)
  
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 5 for calling the TransferGuardTest obj's underlying member method code with example usage: obj.test_nesting() without return types