code: def retrieve(self):
      last_action = self.memory[self.index]
      self.index = 0 if self.index == self.capacity else self.index + 1
      return last_action
  
file_path: FinRL/finrl/agents/portfolio_optimization/utils.py
imports: from __future__ import annotations
  from collections import deque
  import numpy
  from torch.utils.data.dataset import IterableDataset
label_desc: Use image node_id 3 for calling the PVM obj's underlying member method code with example usage: obj.retrieve() and returns: last_action