code: def test_types(self):
      matches = find_closest_matches([], [])
      self.assertIsInstance(matches, np.ndarray)
      self.assertEqual(matches.dtype, int)
      self.assertIsInstance(find_closest_matches([], []), np.ndarray)
  
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 TestFindClosestMatchesFunction obj's underlying member method code with example usage: obj.test_types() without return types