code: def test_mybar_sub():
      # NOTE: we use the constructor because from_raw_data calls
      # .plot() internally, causing to display the individual plots
      # whihc we do not want to test
      one = _example.MyBar({"apple": 2, "banana": 3})
      another = _example.MyBar({"apple": 1, "banana": 5})
      one - another
  
file_path: sklearn-evaluation/tests/test_bar.py
imports: from functools import partial
  from matplotlib.testing.decorators import image_comparison
  from sklearn_evaluation.plot import _example
label_desc: Use image node_id 4 for calling a global function with example usage: test_mybar_sub() without return types