code: def df():
      return pd.DataFrame(
          dict(
              user=[1, 3, 2],
              item=[8, 7, 7],
              rating=[1, 5, 3],
              timestamp=[1, 2, 3],
          )
      )
  
file_path: recommenders/tests/unit/recommenders/models/test_vowpal_wabbit.py
imports: import os
  import pytest
  from unittest import mock
  import pandas
  from recommenders.models.vowpal_wabbit.vw import VW
label_desc: Use image node_id 1 for calling a global function with example usage: df() and returns: pd