class_docstr: MNISTDigitClassifier handler class. This handler extends class ImageClassifier from image_classifier.py, a
  default handler. This handler takes image as a tensor and returns the number in that image.
  
  Here method postprocess() has been overridden while others are reused from parent class.
docstr: Preprocess the data, fetches the image from the request body and converts to torch tensor.
  Args:
      data (list): Image to be sent to the model for inference.
  Returns:
      tensor: A torch tensor
code: def preprocess(self, data):
      """Preprocess the data, fetches the image from the request body and converts to torch tensor.
      Args:
          data (list): Image to be sent to the model for inference.
      Returns:
          tensor: A torch tensor
      """
      return torch.as_tensor(data[0]["body"]["image"])
  
file_path: serve/examples/image_classifier/mnist/torchdata/mnist_handler.py
imports: import numpy
  import torch
  from torch.profiler import ProfilerActivity
  from torchvision import transforms
  from ts.torch_handler.image_classifier import ImageClassifier
label_desc: Use image node_id 2 for calling the MNISTDigitClassifier obj's underlying member method code with example usage: obj.preprocess(data) and returns: torch