pub trait AnnotationsProvider {
    // Required method
    fn annotations(&self) -> Option<Vec<String>>;
    // Provided method
    fn has_annotation(&self, annotation: &str) -> bool { ... }
}pub trait AnnotationsProvider {
    // Required method
    fn annotations(&self) -> Option<Vec<String>>;
    // Provided method
    fn has_annotation(&self, annotation: &str) -> bool { ... }
}