Minesweeper LeetCode solution in Python

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class Solution:
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    def calMines(self, board, x, y):
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        directions = [
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            (-1, -1),
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            (0, -1),
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            (1, -1),
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            (1, 0),
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            (1, 1),
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            (0, 1),
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            (-1, 1),
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            (-1, 0),
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        ]
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        mines = 0
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        for d in directions:
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            r, c = x + d[0], y + d[1]
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            if self.isValid(board, r, c) and (board[r][c] == "M" or board[r][c] == "X"):
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                mines += 1
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        return mines
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    def updateBoard(self, board: List[List[str]], click: List[int]) -> List[List[str]]:
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        x, y = click[0], click[1]
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        options = []
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        if board[x][y] == "M":
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            board[x][y] = "X"
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        else:
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            count = self.calMines(board, x, y)
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            if count == 0:
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                board[x][y] = "B"
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                for r in range(x - 1, x + 2):
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                    for c in range(y - 1, y + 2):
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                        if self.isValid(board, r, c) and board[r][c] != "B":
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                            self.updateBoard(board, [r, c])
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            else:
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                board[x][y] = str(count)
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        return board
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    def isValid(self, board, a, b):
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        return 0 <= a < len(board) and 0 <= b < len(board[0])