class_docstr: PyTorch Lightning implementation of PPO.
  
  Example:
      model = PPOLightning("CartPole-v0")
  Train:
      trainer = Trainer()
      trainer.fit(model)
docstr: Initialize the Replay Buffer dataset used for retrieving experiences.
code: def _dataloader(self) -> DataLoader:
      """Initialize the Replay Buffer dataset used for retrieving experiences."""
      dataset = ExperienceSourceDataset(
          self.generate_trajectory_samples
      )
      return DataLoader(dataset=dataset, batch_size=self.batch_size)
  
imports: import argparse
  from typing import Callable, Iterator, List, Tuple
  import gym
  import torch
  from lightning.pytorch import LightningModule, Trainer, cli_lightning_logo, seed_everything
  from torch import nn
  from torch.distributions import Categorical, Normal
  from torch.optim.optimizer import Optimizer
  from torch.utils.data import DataLoader, IterableDataset
label_desc: Use image node_id 11 for calling the PPOLightning obj's underlying member method code with example usage: obj._dataloader() and returns: DataLoader