code: def df():
      return DataFrame([[1, 2], [2, 4]], columns=["A", "B"])
  
imports: import gc
  import numpy
  import pytest
  from pandas import DataFrame, IndexSlice, Series
  import matplotlib
  from pandas.io.formats.style import Styler
label_desc: Use image node_id 2 for calling a global function with example usage: df() and returns: DataFrame