class Dog {

    public $var;
    private static $instance;

    private function __construct() {}
    private function __clone() {}

    function i18n() {
        // Load text domain. Whilst relevant to the plugin, it isn't directly relevant to the class.
    }

    function enqueue_scripts() {
        // Enqueue styles and scripts. Whilst relevant to the plugin, it isn't directly relevant to the class.
    }

    function sleep() {
        // The things in this method are directly related to the class.
    }

    function eat() {
        // The things in this method are directly related to the class.
    }

    function play() {
        // The things in this method are directly related to the class.
    }

    static function get_instance() {
        if ( self::get_instance() == NULL )
            self::$instance = new Dog;

        return self::$instance;
    }
}