board=[['.','6','1','.','3','.','.','2','.'], ['.','5','.','.','.','8','1','.','7'], ['.','.','.','.','.','7','.','3','4'], ['5','7','.','3','.','.','9','.','.'], ['1','9','.','7','.','.','.','.','.'], ['8','.','2','4','.','.','.','6','.'], ['.','4','.','.','1','.','2','5','.']] def check_node_choices(self, board, x, y): """ 检查节点所有可能性 """ choices = ['1', '2', '3', '4', '5', '6', '7', '8', '9'] for one in board[x]: if one in choices: choices.remove(one) for i in range(9): if board[i][y] in choices: choices.remove(board[i][y]) bx, by = (x // 3) * 3, (y // 3) * 3 for i in range(bx, bx + 3): for j in range(by, by+3): if board[i][j] in choices: choices.remove(board[i][j]) return choices for i in range(9): for j in range(9): if board[i][j] != '.': continue choices = self.check_node_choices(board, i, j) if not choices: pass while choices: board[i][j] = choices.pop() self.solveSudoku(board) if all('.' not in board[m] for m in range(i, 9)): pass board[i][j] = '.' if not choices: pass pass 这个程序怎么改正

根据您提供的代码，我注意到您正在尝试使用递归方法来解决数独问题。不过，我注意到您的代码中存在一些问题。首先，您定义了一个`check_node_choices`函数，但尝试在一个类中使用它作为实例方法。如果您想在类中使用它，应该将其定义为类方法或静态方法，并使用适当的修饰符。其次，您在循环中使用了`pass`语句，这会导致无限循环。最后，您没有提供完整的代码，因此我无法确定您的`solveSudoku`函数的实现。

以下是对您提供的代码进行修改和改正的示例：

class SudokuSolver:
    @staticmethod
    def check_node_choices(board, x, y):
        """
        检查节点所有可能性
        """
        choices = ['1', '2', '3', '4', '5', '6', '7', '8', '9']
        for one in board[x]:
            if one in choices:
                choices.remove(one)
        for i in range(9):
            if board[i][y] in choices:
                choices.remove(board[i][y])
        bx, by = (x // 3) * 3, (y // 3) * 3
        for i in range(bx, bx + 3):
            for j in range(by, by + 3):
                if board[i][j] in choices:
                    choices.remove(board[i][j])
        return choices

    @staticmethod
    def solve_sudoku(board):
        for i in range(9):
            for j in range(9):
                if board[i][j] != '.':
                    continue
                choices = SudokuSolver.check_node_choices(board, i, j)
                if not choices:
                    return False
                while choices:
                    board[i][j] = choices.pop()
                    if SudokuSolver.solve_sudoku(board):
                        return True
                    board[i][j] = '.'
                return False
        return True

# 创建一个 SudokuSolver 实例并调用 solve_sudoku 方法
solver = SudokuSolver()
solver.solve_sudoku(board)

通过以上修改，您应该能够正确地解决数独问题。请注意，我将`check_node_choices`函数和`solve_sudoku`函数定义为了静态方法，这意味着您无需实例化类就可以调用它们。另外，我还更正了循环中的`pass`语句，以避免无限循环的问题。