code: def load_tests(loader, tests, pattern):
      tests.addTest(doctest.DocTestSuite(difflib))
      return tests
  
imports: import difflib
  from test.support import findfile
  import unittest
  import doctest
  import sys
label_desc: Use image node_id 2 for calling a global function with example usage: load_tests(loader, tests, pattern) and returns: tests