message: Update documentation for using pruning and contrib/slim training utility
diff: @@ -33,11 +33,14 @@ to support training of pruned models
  # Create the train_op
  train_op = slim.learning.create_train_op(total_loss, optimizer)
  - # Set up sparsity
  - sparsity = pruning.setup_gradual_sparsity(self.global_step)
  + # Parse pruning hyperparameters
  + pruning_hparams = pruning.get_pruning_hparams().parse(FLAGS.pruning_hparams)
  - # Create mask update op
  - mask_update_op = pruning.add_mask_update_ip(sparsity)
  + # Create a pruning object using the pruning_hparams
  + p = pruning.Pruning(pruning_hparams)
  +
  + # Add mask update ops to the graph
  + mask_update_op = p.conditional_mask_update_op()
  # Run training.
  learning.train(train_op,
  