curriculum/challenges/english/blocks/learn-classes-and-objects-by-building-a-sudoku-solver/6606cc754a8834509cd0afb6.md
Another thing to check is if a number can be inserted in a 3x3 square.
Inside the Board class, create a method named valid_in_square with four parameters: self, row, col, and num. Where row, col, and num represent the row index, the column index, and the number to be checked, respectively.
You should create a new method named valid_in_square within the Board class.
({ test: () => assert(runPython(`_Node(_code).find_class("Board").has_function("valid_in_square")`)) })
Your valid_in_square method should have four parameters: self, row, col, and num, in this order.
({ test: () => assert(runPython(`_Node(_code).find_class("Board").find_function("valid_in_square").has_args("self, row, col, num")`)) })
class Board:
def __init__(self, board):
self.board = board
def find_empty_cell(self):
for row, contents in enumerate(self.board):
try:
col = contents.index(0)
return row, col
except ValueError:
pass
return None
def valid_in_row(self, row, num):
return num not in self.board[row]
def valid_in_col(self, col, num):
return all(self.board[row][col] != num for row in range(9))
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puzzle = [
[0, 0, 2, 0, 0, 8, 0, 0, 0],
[0, 0, 0, 0, 0, 3, 7, 6, 2],
[4, 3, 0, 0, 0, 0, 8, 0, 0],
[0, 5, 0, 0, 3, 0, 0, 9, 0],
[0, 4, 0, 0, 0, 0, 0, 2, 6],
[0, 0, 0, 4, 6, 7, 0, 0, 0],
[0, 8, 6, 7, 0, 4, 0, 0, 0],
[0, 0, 0, 5, 1, 9, 0, 0, 8],
[1, 7, 0, 0, 0, 6, 0, 0, 5]
]
gameboard = Board(puzzle)