class Board:
def __init__(self,other=None):
self.player = 'X'
self.opponent = 'O'
self.empty = ' '
self.size = 3
self.fields = {}
for y in range(self.size):
for x in range(self.size):
self.fields[x,y] = self.empty
# copy constructor
if other:
self.__dict__ = deepcopy(other.__dict__)