def add(self, v, i, j):
        '''
        Fill in an entry in self.mat
        '''
        self.mat[i][j] = v
        uniqueInsert(self.rows[i], v)
        uniqueInsert(self.cols[j], v)
        sub_i = i // 3 * 3 + j // 3
        uniqueInsert(self.subs[sub_i], v)

        Fill in an entry in self.mat
        
recipes/Python/440542_Sudoku_Solver/recipe-440542.py