0001-single-source-of-truth-009.swift

enum Dependencies {
    // ...
    final class Container {
        // ...
        func register(_ dependency: Any, for key: Dependencies.Name = .default) {
            dependencies.append((key: key, value: dependency))
        }
        
        func resolve<T>(_ key: Dependencies.Name = .default) -> T {
            return (dependencies
                .filter { (dependencyTuple) -> Bool in
                    return dependencyTuple.key == key
                        && dependencyTuple.value is T
                }
                .first)?.value as! T
        }   
    }
    // ...
}