code: def test_types(self):
      errors = calc_absolute_errors(DETECTIONS, ANNOTATIONS)
      self.assertIsInstance(errors, np.ndarray)
      self.assertEqual(errors.dtype, float)
  
imports: from __future__ import absolute_import, division, print_function
  import math
  import unittest
  from collections import OrderedDict
  from madmom.evaluation import *
label_desc: Use image node_id 1 for calling the TestCalcAbsoluteErrorsFunction obj's underlying member method code with example usage: obj.test_types() without return types