Function annotation_reference_candidates 

pub fn annotation_reference_candidates(
    graph: &PythonGraphSource<'_>,
    python: &dyn PythonUsageSource,
    file: &ProjectFile,
    source: &str,
    node: Node<'_>,
    target_self_file: bool,
) -> Option<Vec<CodeUnit>>

Resolve a structured Python annotation reference.

Only AST nodes that occur inside a function return type, parameter type, or annotated-assignment type are considered. In particular, string contents are accepted only in those annotation positions; arbitrary string literals are never interpreted as type expressions.