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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:
 async def dispatch_request( self, request_context: Optional[RequestContext]=None, ) -> ResponseReturnValue: """Dispatch the request to the view function. Arguments: request_context: The request context, optional as Flask omits this argument. """

        request_ = (request_context or _request_ctx_stack.top).request
        if request_.routing_exception is not None:
            raise request_.routing_exception

        if request_.method == 'OPTIONS' and request_.url_rule.provide_automatic_options:
            return await self.make_default_options_response()

        handler = self.view_functions[request_.url_rule.endpoint]
        return await handler(**request_.view_args)