def __missing__(self, key):
        if self.default_factory is None:
            raise KeyError(key)
        else:
            ret = self[key] = self.default_factory(name=key)
            return ret
def line(self, x, y, length, horizontal):
		if horizontal:
			self.board[y,x:x+length] = self.color
		else:
			self.board[y:y+length,x] = self.color