class_docstr: Wrapper that stacks observations along a new final axis.
class_docstr_tok: ["Wrapper","that","stacks","observations","along","a","new","final","axis","."]
code: def reset(self) -> dm_env.TimeStep:
      for stacker in tree.flatten(self._stackers):
          stacker.reset()
      return self._process_timestep(self._environment.reset())
  
file_path: acme/acme/wrappers/frame_stacking.py
imports: import collections
  from acme import types
  from acme.wrappers import base
  import dm_env
  from dm_env import specs
  import numpy
  import tree
label_desc: Use image node_id 3 for calling the FrameStackingWrapper obj's underlying member method code with example usage: obj.reset() and returns: self