code: def load_suite_from_file(self, filename):
          
          suite = unittest.TestSuite()
          rules = Rules(filename, suite)
  
          if not os.path.exists(filename):
              rules.handle_file_does_not_exist()
              return suite
  
          line_generator = self._parser.parse_file(filename)
          return self._load_lines(filename, line_generator, suite, rules)
docs: Load a test suite with test lines from the provided TAP file.
  
          :returns: A ``unittest.TestSuite`` instance