Checking if a sudoku solution is valid

Question

So , I've been working on sudoku puzzles from quite some time . It's almost completed , but stuck regarding how to determine if the solution of that solution is valid . Here is the code ( some description is also given there ) :

These are the three methods I used to do so :

1. Taken from GeeksForGeeks :

def isinRange(board):

            N = 9

            for i in range(0, N):
                for j in range(0, N):

                    if ((board[i][j] <= 0) or (board[i][j] > 9)):
                        return False

        return True

        def isValidSudoku(board):
            N = 9

            if (isinRange(board) == False):
                return False

            unique = [False] * (N + 1)

            for i in range(0, N):
                for m in range(0, N + 1):
                    unique[m] = False

                for j in range(0, N):
                    Z = board[i][j]

                if (unique[Z] == True):
                    return False

                unique[Z] = True

            for i in range(0, N):
                for m in range(0, N + 1):
                    unique[m] = False

                for j in range(0, N):
                    Z = board[j][i]

                if (unique[Z] == True):
                    return False

                unique[Z] = True

            for i in range(0, N - 2, 3):
                for j in range(0, N - 2, 3):
                    for m in range(0, N + 1):
                        unique[m] = False

                for k in range(0, 3):
                    for l in range(0, 3):

                        X = i + k
                        Y = j + l
                        Z = board[X][Y]

                    if (unique[Z] == True):
                        return False

                    unique[Z] = True

            return True

        if (isValidSudoku(self.board)):
            print("Valid")
        else:
            print("Not Valid")

2. Made it myself ( using brute force ) , but didn't work :

# grand_list = []
        # check_list = ['1','2','3','4','5','6','7','8','9']
        # for num in range(81):
        #     grand_list.append(self.mega_dict[f"lineEdit_{num+1}"].text())

        # for var in grand_list:
        #     if var == "":
        #         self.textBrowser.setText("The table is not yet completed .")

        #     elif var not in check_list:
        #         self.textBrowser.setText("Invalid entry / entries .")

        #     else:
        #         row1 = set(self.board[0])
        #         row2 = set(self.board[1])
        #         row3 = set(self.board[2])
        #         row4 = set(self.board[3])
        #         row5 = set(self.board[4])
        #         row6 = set(self.board[5])
        #         row7 = set(self.board[6])
        #         row8 = set(self.board[7])
        #         row9 = set(self.board[8])

        #         column1 = {self.board[num][0] for num in range(9)}
        #         column2 = {self.board[num][1] for num in range(9)}
        #         column3 = {self.board[num][2] for num in range(9)}
        #         column4 = {self.board[num][3] for num in range(9)}
        #         column5 = {self.board[num][4] for num in range(9)}
        #         column6 = {self.board[num][5] for num in range(9)}
        #         column7 = {self.board[num][6] for num in range(9)}
        #         column8 = {self.board[num][7] for num in range(9)}
        #         column9 = {self.board[num][8] for num in range(9)}

        #         grid1 = {self.board[0][0],self.board[0][1],self.board[0][2],self.board[1][0],self.board[1][1],self.board[1][2],self.board[2][0],self.board[2][1],self.board[2][2]}
        #         grid2 = {self.board[0][3],self.board[0][4],self.board[0][5],self.board[1][3],self.board[1][4],self.board[1][5],self.board[2][3],self.board[2][4],self.board[2][5]}
        #         grid3 = {self.board[0][6],self.board[0][7],self.board[0][8],self.board[1][6],self.board[1][7],self.board[1][8],self.board[2][6],self.board[2][7],self.board[2][8]}
        #         grid4 = {self.board[3][0],self.board[3][1],self.board[3][2],self.board[4][0],self.board[4][1],self.board[4][2],self.board[5][0],self.board[5][1],self.board[5][2]}
        #         grid5 = {self.board[3][3],self.board[3][4],self.board[3][5],self.board[4][3],self.board[4][4],self.board[4][5],self.board[5][3],self.board[5][4],self.board[5][5]}
        #         grid6 = {self.board[3][6],self.board[3][7],self.board[3][8],self.board[4][6],self.board[4][7],self.board[4][8],self.board[5][6],self.board[5][7],self.board[5][8]}
        #         grid7 = {self.board[6][0],self.board[6][1],self.board[6][2],self.board[7][0],self.board[7][1],self.board[7][2],self.board[8][0],self.board[8][1],self.board[8][2]}
        #         grid8 = {self.board[6][3],self.board[6][4],self.board[6][5],self.board[7][3],self.board[7][4],self.board[7][5],self.board[8][3],self.board[8][4],self.board[8][5]}
        #         grid9 = {self.board[6][6],self.board[6][7],self.board[6][8],self.board[7][6],self.board[7][7],self.board[7][8],self.board[8][6],self.board[8][7],self.board[8][8]}

        #         if len(row1) == len(row2) == len(row3) == len(row4) == len(row5) == len(row6) == len(row7) == len(row8) == len(row9) == len(column1) == len(column2) == len(column3) == len(column4) == len(column5) == len(column6) == len(column7) == len(column8) == len(column9) == len(grid1) == len(grid2) == len(grid3) == len(grid4) == len(grid5) == len(grid6) == len(grid7) == len(grid8) == len(grid9) == 9:
        #             self.textBrowser.setText("You won")

        #         else:
        #             self.textBrowser.setText("There are still recurring numbers available .")

3. The method I wanted to use ( as it's short and gets the job done ) , but can't -- because I don't know how to do that :

        #         self.winning_list1 = {f"row{num+1}":self.complete_board[num*9:num*9+9] for num in range(9)}
        #         self.winning_list2 = {f"column{num+1}":self.complete_board[num*9:] for num in range(9)}
        #         self.winning_list3 = {f"row{num+1}":self.board[num*9:num*9+9] for num in range(9)}

In the third method , what I actually wanted to do was to put up the rows and columns and grids in a dictionary , using dictionary comprehension , and then to verify if all the elements of those sets are different .

But , all the solutions till now have went in vain . Please help regarding which method to use and how to do it .