Function resolve_package_import 

pub fn resolve_package_import(
    importer: &Path,
    pkg_name: &str,
    module_path: &str,
) -> Result<PathBuf, PackageError>

Resolve pkg_name/module_path to a .lex file on disk.

importer is the file that contains the import statement; it’s used to locate the nearest lex.toml.