class_docstr: A regular replay buffer which stores transition without any additional structure
docstr: Returns the transition in the given index. If the transition does not exist, returns None instead.
  :param transition_index: the index of the transition to return
  :param lock: use write locking if this is a shared memory
  :return: the corresponding transition
docstr_tok: ["Returns","the","transition","in","the","given","index",".","If","the","transition","does","not","exist",",","returns","None","instead",".",":","param","transition_index",":","the","index","of","the","transition","to","return",":","param","lock",":","use","write","locking","if","this","is","a","shared","memory",":","return",":","the","corresponding","transition"]
code: def get_transition(
      self, transition_index: int, lock: bool = True
  ) -> Union[None, Transition]:
      """
      Returns the transition in the given index. If the transition does not exist, returns None instead.
      :param transition_index: the index of the transition to return
      :param lock: use write locking if this is a shared memory
      :return: the corresponding transition
      """
      if lock:
          self.reader_writer_lock.lock_writing()
  
      if self.length() == 0 or transition_index >= self.length():
          transition = None
      else:
          transition = self.transitions[transition_index]
  
      if lock:
          self.reader_writer_lock.release_writing()
  
      return transition
  
imports: from typing import List, Tuple, Union
  import pickle
  import random
  import math
  import numpy
  from rl_coach.core_types import Transition
  from rl_coach.logger import screen
  from rl_coach.memories.memory import Memory, MemoryGranularity, MemoryParameters
  from rl_coach.utils import ReaderWriterLock, ProgressBar
label_desc: Use image node_id 8 for calling the ExperienceReplay obj's underlying member method code with example usage: obj.get_transition(transition_index, lock) and returns: transition