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Solve the following problem using Python, implementing the functions described below, one line at a time
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Description:
 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))