class ServerException implements Exception { final String message; ServerException({required this.message}); } class CacheException implements Exception { final String message; CacheException({required this.message}); } class NetworkException implements Exception { final String message; NetworkException({required this.message}); } class AuthException implements Exception { final String message; AuthException({required this.message}); } class DatabaseException implements Exception { final String message; DatabaseException({required this.message}); }