class_docstr: PyTorch Lightning implementation of PPO.
  
  Example:
      model = PPOLightning("CartPole-v0")
  Train:
      trainer = Trainer()
      trainer.fit(model)
docstr: Initialize Adam optimizer.
code: def configure_optimizers(self) -> List[Optimizer]:
      """Initialize Adam optimizer."""
      optimizer_actor = torch.optim.Adam(
          self.actor.parameters(), lr=self.lr_actor
      )
      optimizer_critic = torch.optim.Adam(
          self.critic.parameters(), lr=self.lr_critic
      )
      return optimizer_actor, optimizer_critic
  
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 9 for calling the PPOLightning obj's underlying member method code with example usage: obj.configure_optimizers() and returns: optimizer_actor,  optimizer_critic