public function add(string $event): void
    {
        if (! $this->has($event)) {
            self::$events[$event] = [];
        }
    }
public function add(string $event): void
    {
        if (! $this->has($event)) {
            self::$events[$event] = [];
        }
    }
public function add ( string $ event ) : void { if ( ! $ this -> has ( $ event ) ) { self :: $ events [ $ event ] = [ ] ; } }
Add a new event.

@param string $event The event

@return void
Add a new event .