code: def optimizer_creator(model, config):
      """Returns optimizer defined upon the model parameters."""
      return torch.optim.SGD(
          model.parameters(), lr=config.get("lr", 1e-2)
      )
  
file_path: BigDL/python/orca/example/learn/horovod/pytorch_estimator.py
imports: import argparse
  import numpy
  import torch
  import torch.nn
  from bigdl.orca import init_orca_context, stop_orca_context
  from bigdl.orca.learn.pytorch import Estimator
label_desc: Use image node_id 2 for calling a global function with example usage: optimizer_creator(model, config) and returns: torch