class_docstr: Fake actor which generates random actions and validates specs.
class_docstr_tok: ["Fake","actor","which","generates","random","actions","and","validates","specs","."]
code: def observe(
      self,
      action: types.NestedArray,
      next_timestep: dm_env.TimeStep,
  ):
      _validate_spec(self._spec.actions, action)
      _validate_spec(self._spec.rewards, next_timestep.reward)
      _validate_spec(self._spec.discounts, next_timestep.discount)
      _validate_spec(self._spec.observations, next_timestep.observation)
  
imports: import threading
  from typing import List, Mapping, Optional, Sequence, Callable, Iterator
  from acme import core
  from acme import specs
  from acme import types
  from acme import wrappers
  import dm_env
  import numpy
  import reverb
  from rlds import rlds_types
  import tensorflow
  import tree
label_desc: Use image node_id 4 for calling the Actor obj's underlying member method code with example usage: obj.observe(action, next_timestep) without return types