/// A simple Dart class for user service.
class UserService {
  /// Login method validates credentials.
  void login(String user, String pass) {
    // implementation
  }

  /// Logout method clears session.
  void logout() {
    // implementation
  }

  /// Static helper method.
  static void helper() {
    // implementation
  }
}

/// Enum representing user status.
enum UserStatus {
  active,
  inactive,
  suspended,
}

/// Abstract class for base service.
abstract class BaseService {
  void init();
}