code: def testObservationSpec(self):
      observation_spec = [
          array_spec.ArraySpec((1, 2, 3), np.int32, "obs1"),
          array_spec.ArraySpec((1, 2, 3), np.float32, "obs2"),
      ]
      time_step_spec = ts.time_step_spec(observation_spec)
  
      self.assertEqual(time_step_spec.observation, observation_spec)
      self.assertEqual(
          time_step_spec.step_type,
          array_spec.ArraySpec([], np.int32, name="step_type"),
      )
      self.assertEqual(
          time_step_spec.reward,
          array_spec.ArraySpec([], np.float32, name="reward"),
      )
      self.assertEqual(
          time_step_spec.discount,
          array_spec.BoundedArraySpec(
              [], np.float32, minimum=0.0, maximum=1.0, name="discount"
          ),
      )
  
imports: from __future__ import absolute_import
  from __future__ import division
  from __future__ import print_function
  import sys
  import numpy
  import tensorflow
  from tf_agents.specs import array_spec
  from tf_agents.specs import tensor_spec
  from tf_agents.trajectories import time_step
  from tf_agents.utils import nest_utils
label_desc: Use image node_id 1 for calling the TimeStepSpecTest obj's underlying member method code with example usage: obj.testObservationSpec() without return types