Method in Python

class puzzle(object):
    def __init__(self):
        self.puzzle8 = [[1,2,3],[4,5,6],[7,8,0]]
    def __getitem__(self,index):
        return self.puzzle8.__getitem__(index)
    def __setitem__(self,index,value):
        return self.puzzle8.__setitem__(index,value)
    def __str__(self):
        return str(self.puzzle8)
    def search(self,a):
        for i in range(0,3):
            for j in range(0,3):
                if a == self.puzzle8[i][j] :
                    return (i,j)
    def swap(self,a,b):
        self.puzzle8[a[0]][a[1]], self.puzzle8[b[0]][b[1]] = self.puzzle8[b[0]][b[1]], self.puzzle8[a[0]][a[1]]
    def left(self):
        point = self.search(0)
        if point[1] == 0 :
            return 'impossible'
        self.swap(point,(point[0],point[1]-1))
        print(self.puzzle8)
    def right(self):
        point = self.search(0)
        if point[1] == 3 :
            return 'impossible'
        self.swap(point,(point[0],point[1]+1))
        print(self.puzzle8)
    def up(self):
        point = self.search(0)
        if point[0] == 0 :
            return 'impossible'
        self.swap(point,(point[0]-1,point[1]))
        print(self.puzzle8)
    def down(self):
        point = self.search(0)
        if point[0] == 2 :
            return 'impossible'
        self.swap(point,(point[0]+1,point[1]))
        print(self.puzzle8)