code: def check_main(argv):
      
      if len(argv) != 1:
          print("Please provide the name of a file to check.")
          return 1
  
      filename = argv[0]
  
      if os.path.exists(filename):
          print(u"Checking existing copy of %s" % filename)
          tef = TamperEvidentFile(filename)
          if tef.validate():
              print(u"Your copy of %s is good" % filename)
          else:
              print(u"Your copy of %s seems to have been edited" % filename)
      else:
          print(u"You don't have a copy of %s" % filename)
  
      return 0
docs: check FILENAME
          Check that FILENAME has not been edited since writing.