code: def setUp(self):
      super().setUp()
      linecache.clearcache()
      self.deleted_file = os_helper.TESTFN + ".1"
      self.modified_file = os_helper.TESTFN + ".2"
      self.unchanged_file = os_helper.TESTFN + ".3"
  
      for fname in (
          self.deleted_file,
          self.modified_file,
          self.unchanged_file,
      ):
          self.addCleanup(os_helper.unlink, fname)
          with open(fname, "w", encoding="utf-8") as source:
              source.write(f'print("I am {fname}")')
  
          self.assertNotIn(fname, linecache.cache)
          linecache.getlines(fname)
          self.assertIn(fname, linecache.cache)
  
      os.remove(self.deleted_file)
      with open(self.modified_file, "w", encoding="utf-8") as source:
          source.write('print("was modified")')
  
imports: import linecache
  import unittest
  import os.path
  import tempfile
  import tokenize
  from test import support
  from test.support import os_helper
label_desc: Use image node_id 1 for calling the LineCacheInvalidationTests obj's underlying member method code with example usage: obj.setUp() without return types