import unittest


class Life(object):
    def __init__(self, state):
        self.state = state

    def next(self):
        cells_to_consider = set()

        for x, y in self.state:
            for i in range(-1, 2):
                for j in range(-1, 2):
                    cells_to_consider.add((x+i, y+j))
        
        new_state = set()
        for x, y in cells_to_consider:
            if self.isAlive((x, y) in self.state, self.countNeighbours(x, y)):
                new_state.add((x, y))

        return Life(new_state)

    def isAlive(self, current, neigh):
        if neigh == 2:
            return current
        elif neigh == 3:
            return True
        else:
            return False

    def countNeighbours(self, x, y):
        sum = 0
        for i in range(-1, 2):
            for j in range(-1, 2):
                if i == 0 and j == 0:
                    continue

                if (x+i, y+j) in self.state:
                    sum += 1

        return sum


class LifeTest(unittest.TestCase):
    # YOLO
    pass


if __name__ == '__main__':
    unittest.main()