private void FocusPlayer(PlayerBehaviour player)
    {
        //on se retire de la liste du joueur focus précédent
        if (focusedPlayer != null && focusedPlayer.attackingEnemies != null && focusedPlayer.attackingEnemies.Contains(this))
        {
            focusedPlayer.attackingEnemies.Remove(this);
        }

        focusedPlayer = player;
        focusedPlayer.AddAttackingEnemy(this);
    }