old_contents: """Saved source codes for "Dive into Deep Learing" (https://d2l.ai).
  
  Please import d2l by one of the following ways:
  
  from d2l import mxnet as d2l  # Use MXNet as the backend
  from d2l import torch as d2l  # Use PyTorch as the backend
  
  """
  
  __version__ = "1.2.0"
  
new_contents: """Saved source code for "Dive into Deep Learing" (https://d2l.ai).
  
  Please import d2l by one of the following ways:
  
  from d2l import mxnet as d2l  # Use MXNet as the backend
  from d2l import torch as d2l  # Use PyTorch as the backend
  from d2l import tensorflow as d2l  # Use TensorFlow as the backend
  
  """
  
  __version__ = "1.2.0"
  
subject: add tf instructions