docs: def LegacyKextunload(self, cf_bundle_identifier):
      """Unload a kext by forking into kextunload."""
      error_code = OS_SUCCESS
      bundle_identifier = self.CFStringToPystring(cf_bundle_identifier)
      try:
        subprocess.check_call(['/sbin/kextunload', '-b', bundle_identifier])
      except subprocess.CalledProcessError as cpe:
        logging.debug('failed to unload %s:%s', bundle_identifier, str(cpe))
        error_code = -1
      return error_code