code: def _imagenet_preprocess_tf(x):
      return (x / 127.5) - 1
  
imports: import math
  import os
  import tarfile
  import click
  import keras
  import numpy
  import tensorflow
  from image_pyfunc import decode_and_resize_image, log_model
  from keras.applications import vgg16
  from keras.callbacks import Callback
  from keras.layers import Dense, Flatten, Input, Lambda
  from keras.models import Model
  from keras.utils import np_utils
  from sklearn.model_selection import train_test_split
  import mlflow
  from mlflow.models import infer_signature
label_desc: Use image node_id 3 for calling a global function with example usage: _imagenet_preprocess_tf(x) and returns: unknown