Function yaml_from_str 

pub fn yaml_from_str<T: DeserializeOwned>(
    content: &str,
    location: &str,
) -> Result<T>

Parse YAML content tolerating duplicate mapping keys (last value wins).

If duplicate keys are detected, a warning is emitted (suppressible via --quiet) and the content is re-parsed with DuplicateKeyPolicy::LastWins to match PyYAML’s behavior. The result is deserialized via serde_json::Value as an intermediate to avoid serde’s struct-level duplicate field rejection.