Register input to the request handlers list.

        :param request_handler: Request Handler instance to be
            registered.
        :type request_handler: AbstractRequestHandler
        :return: None

def add_request_handler(self, request_handler):
        # type: (AbstractRequestHandler) -> None
        """Register input to the request handlers list.

        :param request_handler: Request Handler instance to be
            registered.
        :type request_handler: AbstractRequestHandler
        :return: None
        """
        if request_handler is None:
            raise RuntimeConfigException(
                "Valid Request Handler instance to be provided")

        if not isinstance(request_handler, AbstractRequestHandler):
            raise RuntimeConfigException(
                "Input should be a RequestHandler instance")

        self.request_handler_chains.append(GenericRequestHandlerChain(
            request_handler=request_handler))