example from https://tarquin-the-brave.github.io/blog/posts/rust-serde/

yaml_to_json_failure.rs

let some_yaml = r#"
    [5,6]: true
    "#;

let try_yaml = serde_yaml::from_str::<serde_yaml::Value>(some_yaml);
let try_json = serde_yaml::from_str::<serde_json::Value>(some_yaml);

assert!(try_yaml.is_ok());
assert!(try_json.is_err());