code: def filter_non_target(df):
      train_df = df[df[target] != -1]
      return train_df
  
imports: import bigdl.orca.data.pandas
  from bigdl.orca.data.transformer import *
label_desc: Use image node_id 3 for calling a global function with example usage: filter_non_target(df) and returns: train_df