code: import argparse
  import json
  import os
  import pickle
  import sys
  import sagemaker_containers
  import pandas as pd
  import numpy as np
  import torch
  import torch.nn as nn
  import torch.optim as optim
  import torch.utils.data
  
  from model import LSTMClassifier
  
  from utils import review_to_words, convert_and_pad
  
  def model_fn(model_dir):
      """Load the PyTorch model from the `model_dir` directory."""
      print("Loading model.")
  
      # First, load the parameters used to create the model.
      model_info = {}
      model_info_path = os.path.join(model_dir, 'model_info.pth')
      with open(model_info_path, 'rb') as f:
          model_info = torch.load(f)
  
      print("model_info: {}".format(model_info))
  
      # Determine the device and construct the model.
      device = torch.device("cuda" if torch.cuda.is_available() else "cpu")
      model = LSTMClassifier(model_info['embedding_dim'], model_info['hidden_dim'], model_info['vocab_size'])
  
      # Load the store model parameters.
      model_path = os.path.join(model_dir, 'model.pth')
      with open(model_path, 'rb') as f:
          model.load_state_dict(torch.load(f))
  
      # Load the saved word_dict.
      word_dict_path = os.path.join(model_dir, 'word_dict.pkl')
      with open(word_dict_path, 'rb') as f:
          model.word_dict = pickle.load(f)
  
      model.to(device).eval()
  
      print("Done loading model.")
      return model
  
  def input_fn(serialized_input_data, content_type):
      print('Deserializing the input data.')
      if content_type == 'text/plain':
          data = serialized_input_data.decode('utf-8')
          return data
      raise Exception('Requested unsupported ContentType in content_type: ' + content_type)
  
  def output_fn(prediction_output, accept):
      print('Serializing the generated output.')
      return str(prediction_output)
  
  def predict_fn(input_data, model):
      print('Inferring sentiment of input data.')
  
      device = torch.device("cuda" if torch.cuda.is_available() else "cpu")
      
      if model.word_dict is None:
          raise Exception('Model has not been loaded properly, no word_dict.')
      
      # TODO: Process input_data so that it is ready to be sent to our model.
      #       You should produce two variables:
      #         data_X   - A sequence of length 500 which represents the converted review
      #         data_len - The length of the review
  
      data_X , data_len = convert_and_pad(model.word_dict, review_to_words(input_data))
  
      # Using data_X and data_len we construct an appropriate input tensor. Remember
      # that our model expects input data of the form 'len, review[500]'.
      data_pack = np.hstack((data_len, data_X))
      data_pack = data_pack.reshape(1, -1)
      
      data = torch.from_numpy(data_pack)
      data = data.to(device)
  
      # Make sure to put the model into evaluation mode
      model.eval()
  
      # TODO: Compute the result of applying the model to the input data. The variable `result` should
      #       be a numpy array which contains a single integer which is either 1 or 0
      
      with torch.no_grad():
          y = model.forward(data)
      
      result = np.round(y.numpy())
      return result
  
apis: torch.load torch.no_grad numpy.hstack torch.from_numpy torch.cuda.is_available