fn main() {
let enabled_versions_027 = (31..=35)
.map(|v| format!("V1_{v}"))
.filter(|v| std::env::var(format!("CARGO_FEATURE_K8S_OPENAPI027_{v}")).is_ok())
.collect::<std::collections::BTreeSet<_>>();
assert!(
enabled_versions_027.len() <= 1,
"\nOnly one `k8s_openapi*` feature may be enabled at a given time, found: {enabled_versions_027:?}`\n"
);
}