code: def test_matching_blocks_cache(self):
      # Issue #21635
      s = difflib.SequenceMatcher(None, "abxcd", "abcd")
      first = s.get_matching_blocks()
      second = s.get_matching_blocks()
      self.assertEqual(second[0].size, 2)
      self.assertEqual(second[1].size, 2)
      self.assertEqual(second[2].size, 0)
  
imports: import difflib
  from test.support import findfile
  import unittest
  import doctest
  import sys
label_desc: Use image node_id 3 for calling the TestSFbugs obj's underlying member method code with example usage: obj.test_matching_blocks_cache() without return types