code: def testTruncation(self):
      observation = -1
      reward = 2.0
      discount = 1.0
      time_step = ts.truncation(
          observation, reward, discount
      )  # pytype: disable=wrong-arg-types
  
      self.assertEqual(ts.StepType.LAST, time_step.step_type)
      self.assertEqual(-1, time_step.observation)
      self.assertEqual(2.0, time_step.reward)
      self.assertEqual(1.0, time_step.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 8 for calling the TimeStepTest obj's underlying member method code with example usage: obj.testTruncation() without return types