fn normalize_features(
original_features: Option<&BTreeMap<FeatureName, Vec<String>>>,
) -> CargoResult<Option<BTreeMap<FeatureName, Vec<String>>>>
fn normalize_features(
original_features: Option<&BTreeMap<FeatureName, Vec<String>>>,
) -> CargoResult<Option<BTreeMap<FeatureName, Vec<String>>>>