class_docstr: ## Trainer
class_docstr_tok: ["#","#","Trainer"]
docstr: #### Normalize advantage function
docstr_tok: ["#","#","#","#","Normalize","advantage","function"]
code: def _normalize(adv: torch.Tensor):
      """#### Normalize advantage function"""
      return (adv - adv.mean()) / (adv.std() + 1e-8)
  
imports: from typing import Dict
  import numpy
  import torch
  from torch import nn
  from torch import optim
  from torch.distributions import Categorical
  from labml import monit, tracker, logger, experiment
  from labml.configs import FloatDynamicHyperParam, IntDynamicHyperParam
  from labml_helpers.module import Module
  from labml_nn.rl.game import Worker
  from labml_nn.rl.ppo import ClippedPPOLoss, ClippedValueFunctionLoss
  from labml_nn.rl.ppo.gae import GAE
label_desc: Use image node_id 4 for calling the Trainer obj's underlying member method code with example usage: obj._normalize(adv) and returns: unknown