input: 
  def solve_maze(maze: Maze) -> List[int]:
      """This function solves a given maze represented by a Maze object. The maze can be traversed 
      from the top-left corner to the bottom-right corner. The function returns a list of integers 
      representing the values of the cells in the path from the start to the end.
  
      >>> maze = Maze(3, 3)
      >>> maze._grid = [[1, None, None], [1, 1, None], [None, 1, 1]]
      >>> solve_maze(maze)
      [0, 1, 2, 3]
  
      >>> maze = Maze(2, 2)
      >>> maze._grid = [[1, None], [1, 1]]
      >>> solve_maze(maze)
      [0, 1]
      """
      return maze.solve_maze()
  
output:     def dfs(maze, x, y, path):
          if x == maze.rows - 1 and y == maze.cols - 1:
              return path + [maze._grid[x][y]]
          if x < 0 or x >= maze.rows or y < 0 or y >= maze.cols or maze._grid[x][y] is None:
              return None
          maze._grid[x][y] = None
          for dx, dy in [(0, 1), (1, 0), (0, -1), (-1, 0)]:
              result = dfs(maze, x + dx, y + dy, path + [maze._grid[x][y]])
              if result:
                  return result
          return None
  
      return dfs(maze, 0, 0, [])