code: def save(model_dir, model):
      model.symbol.save(os.path.join(model_dir, "model-symbol.json"))
      model.save_params(os.path.join(model_dir, "model-0000.params"))
  
      signature = [
          {
              "name": data_desc.name,
              "shape": [dim for dim in data_desc.shape],
          }
          for data_desc in model.data_shapes
      ]
      with open(os.path.join(model_dir, "model-shapes.json"), "w") as f:
          json.dump(signature, f)
  
file_path: sagemaker-python-sdk/tests/data/mxnet_mnist/mnist.py
imports: from __future__ import absolute_import
  import argparse
  import gzip
  import json
  import logging
  import os
  import struct
  import mxnet
  import numpy
label_desc: Use image node_id 6 for calling a global function with example usage: save(model_dir, model) without return types