code: def test_flatmapping_init(self):
      # NOTE: FlatMapping is a shim only for `pickle.loads`. The actual immutable
      # map type in Haiku is FlatMap.
      o = data_structures.FlatMapping({})
      self.assertEqual(type(o), dict)
  
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 18 for calling the FlatMappingTest obj's underlying member method code with example usage: obj.test_flatmapping_init() without return types