class ConnectionRegistry { private static $registry = []; public static function set($key, $value) { self::$registry[$key] = $value; } public static function get($key) { if (!isset(self::$registry[$key])) { throw new InvalidArgumentException("{$key} is not registered in the registry"); } return self::$registry[$key]; } } // Usage Example $connection = new PDO('mysql:host=localhost;dbname=mydb', 'user', 'password'); ConnectionRegistry::set('db', $connection); // Later on in the code... $db = ConnectionRegistry::get('db'); $stmt = $db->query('SELECT * FROM my_table');In this example, the static registry is implemented as a simple class with two static methods: `set` and `get`. The `set` method stores a value in the registry using a key that can be used to retrieve the value later. The `get` method retrieves a value from the registry using the key that was used to store it. If the key does not exist in the registry, it throws an exception. The package/library used in this example is PDO, which is a PHP extension for database connections.