class PyramidState:
    def __init__(self, pyramid):
        self.pyramid = pyramid
        self.empty = [5 - len(self.pyramid[0]), 5 - len(self.pyramid[1]), 3 - len(self.pyramid[2])]

    def __str__(self):
        return f"Current pyramid: {self.pyramid}\nCurrently empty slots: {self.empty}"

    def append(self, card, board_index):
        if self.empty[board_index] > 0:
            self.pyramid[board_index].append(card)
            self.empty = [5 - len(self.pyramid[0]), 5 - len(self.pyramid[1]), 3 - len(self.pyramid[2])]
        else:
            raise IndexError("Selected board has no empty slots")