I tried to define a function call in spring ai as below

    @Bean
    @Description("return list of Vets, include their specialist")
    public Function<Void, Collection<Vet>> queryVets() {
        return request -> {
            return vetRepository.findAll();
        };
    }

The input parameter is Void as the function has no input parameter.

But I got the error
com.azure.core.exception.HttpResponseException: Status code 400, “{
“error”: {
“message”: “Invalid schema for function ‘queryVets’: In context=(), object schema missing properties”,
“type”: “invalid_request_error”,
“param”: null,
“code”: null
}
}
“

How can I define a fuction without input parameters?

define a fuction without input parameters