def save(self):
        tmp_path = self.path + '.tmp'
        with open(tmp_path, 'w') as f:
            f.write(json.dumps(self.body_labels.items()))
        os.rename(tmp_path, self.path)
def inc_r(self, ind):
        r, c = self.row_col(ind)
        r += 1
        if r == self.nr:
            r = 0
        if r == (self.nr - 1) and c == (self.nc - 1):
            r = 0
        return self.indx(r, c)