code: def dfs(grid, matrix, height, i, j):
      if i < 0 or i >= len(matrix) or j < 0 or j >= len(matrix[0]):
          return
      if grid[i][j] or matrix[i][j] < height:
          return
      grid[i][j] = True
      dfs(grid, matrix, matrix[i][j], i - 1, j)
      dfs(grid, matrix, matrix[i][j], i + 1, j)
      dfs(grid, matrix, matrix[i][j], i, j - 1)
      dfs(grid, matrix, matrix[i][j], i, j + 1)
  
label_desc: Use image node_id 2 for calling a global function with example usage: dfs(grid, matrix, height, i, j) without return types