3."""Code _Write a function validSolution/ValidateSolution/valid_solution()that accepts a 2D array representing a Sudoku board, and returns trueif it is a valid solution, or false otherwise. The cells of the sudokuboard may also contain 0's, which will represent empty cells.Boards containing one or more zeroes are considered to be invalid solutions.The board is always 9 cells by 9 cells, and every cell only contains integersfrom 0 to 9. (More info at: http://en.wikipedia.org/wiki/Sudoku)""" # Using dict/hash-tablefrom collections import defaultdict def valid_solution_hashtable(board):    for i in range(len(board)):        dict_row = defaultdict(int)        dict_col = defaultdict(int)        for j in range(len(board[0])):            value_row = board[i][j]            value_col = board[j][i]            if not value_row or value_col == 0:                return False            if value_row in dict_row:                return False            else:                dict_row[value_row] += 1.