code: def initialize_optimizer(
      optimizer: keras.optimizers.Optimizer, model: keras.Model
  ) -> None:
      """
      Initializes an optimizer given a model.
  
      Parameters
      ----------
      optimizer
          Optimizer to be initialized.
      model
          Model to be optimized
      """
  
      # Dummy zero gradients.
      zero_grads = [tf.zeros_like(w) for w in model.trainable_weights]
  
      # Apply gradients which don't do nothing.
      optimizer.apply_gradients(
          zip(zero_grads, model.trainable_weights)
      )
  
imports: import os
  import random
  from typing import Any, List, Dict, Callable, Union, Optional, TYPE_CHECKING
  import numpy
  import tensorflow
  import tensorflow.keras
  from alibi.explainers.backends.cfrl_base import CounterfactualRLDataset
  from alibi.models.tensorflow.actor_critic import Actor, Critic
label_desc: Use image node_id 11 for calling a global function with example usage: initialize_optimizer(optimizer, model) without return types