class_docstr: An observer that collects action norm stats.
docstr: Records one environment step.
code: def observe(
      self,
      env: dm_env.Environment,
      timestep: dm_env.TimeStep,
      action: np.ndarray,
  ) -> None:
      """Records one environment step."""
      self._action_norms.append(np.linalg.norm(action))
  
file_path: acme/acme/utils/observers/action_norm.py
imports: from typing import Dict
  from acme.utils.observers import base
  import dm_env
  import numpy
label_desc: Use image node_id 3 for calling the ActionNormObserver obj's underlying member method code with example usage: obj.observe(env, timestep, action) without return types