class_docstr: MockTFEnvironment.
  
  Stores all actions taken in `actions_taken`. The returned values are:
  
  step: FIRST, 1., 0., [0]
  step: MID, 1., 0., [1]
  step: LAST, 0., 1. [2]
  ...repeated
class_docstr_tok: ["MockTFEnvironment",".","Stores","all","actions","taken","in","`","actions_taken","`",".","The","returned","values","are",":","step",":","FIRST",",","1.",",","0.",",","[","0","]","step",":","MID",",","1.",",","0.",",","[","1","]","step",":","LAST",",","0.",",","1",".","[","2","]","...","repeated"]
code: def _current_time_step(self):
      def first():
          return (
              tf.constant(FIRST, dtype=tf.int32),
              tf.constant(0.0, dtype=tf.float32),
              tf.constant(1.0, dtype=tf.float32),
          )
  
      def mid():
          return (
              tf.constant(MID, dtype=tf.int32),
              tf.constant(0.0, dtype=tf.float32),
              tf.constant(1.0, dtype=tf.float32),
          )
  
      def last():
          return (
              tf.constant(LAST, dtype=tf.int32),
              tf.constant(1.0, dtype=tf.float32),
              tf.constant(0.0, dtype=tf.float32),
          )
  
      state_value = tf.math.mod(self._state.value(), 3)
      step_type, reward, discount = tf.case(
          [
              (tf.equal(state_value, FIRST), first),
              (tf.equal(state_value, MID), mid),
              (tf.equal(state_value, LAST), last),
          ],
          exclusive=True,
          strict=True,
      )
      return ts.TimeStep(step_type, reward, discount, state_value)
  
imports: from __future__ import absolute_import
  from __future__ import division
  from __future__ import print_function
  import tensorflow
  from tf_agents import specs
  from tf_agents.environments import tf_environment
  from tf_agents.trajectories import time_step
  from tf_agents.utils import common
label_desc: Use image node_id 2 for calling the TFEnvironmentMock obj's underlying member method code with example usage: obj._current_time_step() and returns: ts, tf,  tf,  tf, tf,  tf,  tf, tf,  tf,  tf