docs: def check_firmware_update_component(func):
      """Checks the firmware update component."""
      @six.wraps(func)
      def wrapper(self, filename, component_type):
          """Wrapper around ``update_firmware`` call.
  
          :param filename: location of the raw firmware file.
          :param component_type: Type of component to be applied to.
          """
          component_type = component_type and component_type.lower()
          if (component_type not in SUPPORTED_FIRMWARE_UPDATE_COMPONENTS):
              msg = ("Got invalid component type for firmware update: "
                     "``update_firmware`` is not supported on %(component)s" %
                     {'component': component_type})
              LOG.error(self._(msg))  # noqa
              raise exception.InvalidInputError(msg)
  
          return func(self, filename, component_type)
  
      return wrapper