code: def testNestFlatten(self):
      layer = nest_map.NestFlatten()
      outputs = layer({"a": 1, "b": 2})
      self.assertEqual(self.evaluate(outputs), [1, 2])
  
imports: from __future__ import absolute_import
  from __future__ import division
  from __future__ import print_function
  import os
  from absl import flags
  import tensorflow.compat.v2
  from tf_agents.keras_layers import inner_reshape
  from tf_agents.networks import nest_map
  from tf_agents.networks import sequential
  from tf_agents.policies import policy_saver
  from tf_agents.policies import tf_policy
  from tf_agents.specs import tensor_spec
  from tf_agents.trajectories import policy_step
  from tf_agents.trajectories import time_step
  from tf_agents.utils import common
  from tf_agents.utils import nest_utils
  from tf_agents.utils import test_utils
label_desc: Use image node_id 1 for calling the NestFlattenTest obj's underlying member method code with example usage: obj.testNestFlatten() without return types