code: def test_setattr(self):
      f = FlatMap(dict(a=1))
      with self.assertRaises(AttributeError):
          # Existing attr.
          f.a = 4  # pytype: disable=not-writable
      with self.assertRaises(AttributeError):
          # New attr.
          f.c = 4
  
imports: import collections
  import copy
  import pickle
  import threading
  from absl.testing import absltest
  from absl.testing import parameterized
  import cloudpickle
  import dill
  from haiku._src import data_structures
  import jax
  import tree
label_desc: Use image node_id 3 for calling the FlatMappingTest obj's underlying member method code with example usage: obj.test_setattr() without return types