code: def test_errors(self):
      with self.assertRaises(ValueError):
          combine_events(np.arange(6).reshape((2, 3)), 0.5)
      with self.assertRaises(ValueError):
          combine_events(EVENTS, 0.5, "foo")
  
imports: from __future__ import absolute_import, division, print_function
  import unittest
  from os.path import join
  from madmom.utils import *
  from .None import ACTIVATIONS_PATH, ANNOTATIONS_PATH, AUDIO_PATH, DATA_PATH, DETECTIONS_PATH
  from .test_evaluation_notes import ANNOTATIONS
label_desc: Use image node_id 4 for calling the TestCombineEventsFunction obj's underlying member method code with example usage: obj.test_errors() without return types