Confuse with Backjumping algorithm

[ThuriyaThwin]

Hi! I confuse about backjumping algorithm and could you explain me a little detail please. The point I stuck is

if status:
                return True, new_grid, steps, set()
            elif (next_row + 8*next_column) not in new_conflicts:
                return False, grid, num_steps, new_conflicts
            else:
                new_conflicts.remove(next_row + 8*next_column)
                conflicts = conflicts.union(new_conflicts)

            num_steps = steps
            grid[next_row, next_column] = 0