code: def train(predictor, df):
      predictor.learn(df)
  
file_path: lightwood/tests/integration/basic/test_save_and_load.py
imports: from lightwood.api.high_level import code_from_problem, predictor_from_code, predictor_from_state
  from lightwood.api.types import ProblemDefinition
  import unittest
  import multiprocessing
  import os
  import pandas
label_desc: Use image node_id 2 for calling a global function with example usage: train(predictor, df) without return types