code: def change_val(df):
      df["target"] = df["target"] - 1
      return df
  
file_path: BigDL/python/orca/tutorial/xshards/tabular_playground_series.py
imports: from sklearn.model_selection import train_test_split
  import torch
  import torch.nn
  import torch.optim
  from bigdl.orca import init_orca_context, stop_orca_context
  import bigdl.orca.data.pandas
  from bigdl.orca.data.transformer import *
  from bigdl.orca.learn.pytorch import Estimator
  from bigdl.orca.learn.metrics import Accuracy
label_desc: Use image node_id 2 for calling a global function with example usage: change_val(df) and returns: df