class Plansza:
    _instance = None

    def __new__(cls, *args, **kwargs):
      if not cls._instance:
        cls._instance = super().__new__(cls)
      return cls._instance

    def __init__(self):
        if not hasattr(self, '_initialized'):      
            self.pole = [['O' for x in range(5)] for y in range(5)]
            self._initialized = True

    def dodaj_jednostke(self, jednostka, x, y):
        x -= 1
        y -= 1
        if self.czy_zajete(x, y):
            print('Nie mozna dodać jednostki na tym polu')
        else:
            self.pole[x][y] = jednostka
        self.wyswietl()

    def usun_jednostke(self, x, y):
        x -= 1
        y -= 1
        if self.czy_zajete(x, y):
            self.pole[x][y] = 'O'
        else:
            print('To pole juz jest puste')
        self.wyswietl()

    def czy_zajete(self, x, y):
        if self.pole[x][y] == 'O':
            return False
        return True

    def wyswietl(self):
        print()
        for y in range(5):
            for x in range(5):
                print(self.pole[x][y], end=' ')
            print()
        print()