docstr: Append experience to buffer. When buffer is full, it pops
     an old experience.
  
  Args:
    experience: experience to be saved.
docstr_tok: ["Append","experience","to","buffer",".","When","buffer","is","full",",","it","pops","an","old","experience",".","Args",":","experience",":","experience","to","be","saved","."]
code: def append(self, experience):
      """Append experience to buffer. When buffer is full, it pops
         an old experience.
  
      Args:
        experience: experience to be saved.
      """
      self.buffer.append(experience)
  
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 ReplayBuffer obj's underlying member method code with example usage: obj.append(experience) without return types