class_docstr: Wrapper around a replay buffer in order to use HER.
  This implementation is inspired by to the one found in https://github.com/NervanaSystems/coach/.
  
  :param replay_buffer: (ReplayBuffer)
  :param n_sampled_goal: (int) The number of artificial transitions to generate for each actual transition
  :param goal_selection_strategy: (GoalSelectionStrategy) The method that will be used to generate
      the goals for the artificial transitions.
  :param wrapped_env: (HERGoalEnvWrapper) the GoalEnv wrapped using HERGoalEnvWrapper,
      that enables to convert observation to dict, and vice versa
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docstr: Sample a batch of achieved goals according to the sampling strategy.
  
  :param episode_transitions: ([tuple]) list of the transitions in the current episode
  :param transition_idx: (int) the transition to start sampling from
  :return: (np.ndarray) an achieved goal
docstr_tok: ["Sample","a","batch","of","achieved","goals","according","to","the","sampling","strategy",".",":","param","episode_transitions",":","(","[","tuple","]",")","list","of","the","transitions","in","the","current","episode",":","param","transition_idx",":","(","int",")","the","transition","to","start","sampling","from",":","return",":","(","np.ndarray",")","an","achieved","goal"]
code: def _sample_achieved_goals(self, episode_transitions, transition_idx):
      """
      Sample a batch of achieved goals according to the sampling strategy.
  
      :param episode_transitions: ([tuple]) list of the transitions in the current episode
      :param transition_idx: (int) the transition to start sampling from
      :return: (np.ndarray) an achieved goal
      """
      return [
          self._sample_achieved_goal(
              episode_transitions, transition_idx
          )
          for _ in range(self.n_sampled_goal)
      ]
  
file_path: stable-baselines/stable_baselines/her/replay_buffer.py
imports: import copy
  from enum import Enum
  import numpy
label_desc: Use image node_id 7 for calling the HindsightExperienceReplayWrapper obj's underlying member method code with example usage: obj._sample_achieved_goals(episode_transitions, transition_idx) and returns: unknown