code: def pairwise_target_frame():
      """Pairwise target frame for test_pairwise"""
      return DataFrame([[2, 4], [1, 2], [5, 2], [8, 1]], columns=[0, 1])
  
imports: import numpy
  import pytest
  from pandas.compat import IS64
  from pandas import DataFrame, Index, MultiIndex, Series, date_range
  import pandas._testing
  from pandas.core.algorithms import safe_sort
label_desc: Use image node_id 2 for calling a global function with example usage: pairwise_target_frame() and returns: DataFrame