Number of Enclaves LeetCode solution in Python

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class Solution:
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    def recursion(self, grid, row, col, m, n):
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        if 0 <= row < m and 0 <= col < n and grid[row][col] == 1:
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            grid[row][col] = "t"
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            self.recursion(grid, row + 1, col, m, n)
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            self.recursion(grid, row - 1, col, m, n)
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            self.recursion(grid, row, col + 1, m, n)
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            self.recursion(grid, row, col - 1, m, n)
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    def numEnclaves(self, grid: List[List[int]]) -> int:
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        m, n = len(grid), len(grid[0])
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        if not m or not n:
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            return 0
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        # mark all boundary lands and neighbors with 0
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        for row in range(m):
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            self.recursion(grid, row, 0, m, n)
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            self.recursion(grid, row, n - 1, m, n)
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        for col in range(n):
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            self.recursion(grid, 0, col, m, m)
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            self.recursion(grid, m - 1, col, m, n)
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        result = 0
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        for i in range(m):
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            for j in range(n):
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                if grid[i][j] == 1:
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                    result += 1
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        return result