class_docstr: An observer that collects action norm stats.
docstr: Observes the initial state.
code: def observe_first(
      self, env: dm_env.Environment, timestep: dm_env.TimeStep
  ) -> None:
      """Observes the initial state."""
      self._action_norms = []
  
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 2 for calling the ActionNormObserver obj's underlying member method code with example usage: obj.observe_first(env, timestep) without return types