class_docstr: Fake Learner.
class_docstr_tok: ["Fake","Learner","."]
code: def step(self):
      self.step_counter += 1
  
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 2 for calling the Learner obj's underlying member method code with example usage: obj.step() without return types