def METHOD_NAME(operator: str, **kwargs) -> str:
    if operator == OperatorType.METALLB:
        api_ip = kwargs.get("api_ip")
        ingress_ip = kwargs.get("ingress_ip")
        if api_ip and ingress_ip:
            return f'{{"api_ip": "{api_ip}", "ingress_ip": "{ingress_ip}"}}'
        raise ValueError(f"MetalLB properties are missing or invalid, got {api_ip} {ingress_ip}")
    return ""