code: def test_conversion(self):
      # conversion from list should work
      e = OnsetEvaluation([0], [0])
      self.assertIsInstance(e.tp, np.ndarray)
      self.assertIsInstance(e.fp, np.ndarray)
      self.assertIsInstance(e.tn, np.ndarray)
      self.assertIsInstance(e.fn, np.ndarray)
      self.assertIsInstance(e.errors, np.ndarray)
      # conversion from single values should work
      e = OnsetEvaluation(0, 0)
      self.assertIsInstance(e.tp, np.ndarray)
      self.assertIsInstance(e.fp, np.ndarray)
      self.assertIsInstance(e.tn, np.ndarray)
      self.assertIsInstance(e.fn, np.ndarray)
      self.assertIsInstance(e.errors, np.ndarray)
  
imports: from __future__ import absolute_import, division, print_function
  import math
  import unittest
  from madmom.evaluation.onsets import *
  from .None import ANNOTATIONS_PATH, DETECTIONS_PATH
label_desc: Use image node_id 2 for calling the TestOnsetEvaluationClass obj's underlying member method code with example usage: obj.test_conversion() without return types