Break Walls

Randomness is fun, but it can be tough to debug your application if each time you run it, it behaves slightly differently. We'll add an optional "seed" parameter that can be toggled on and off to ensure that the randomness behaves the same every time when seeded. It will only be used for testing and debugging.

1. Update the Maze class constructor to accept an optional seed that defaults to None. Then, in your constructor, if the seed isn't None, call random.seed(seed).

2. Add a new data member to the cell class called visited and initialize it to False. This is how we'll track which cells have had their walls broken.
3. Create a recursive __break_walls_r(self, i, j) method. It's a depth-first traversal through the cells, breaking down walls as it goes. I'll describe the algorithm I used below, but feel free to write your own from scratch if you're up to it!

Once you have implemented the changes above, run your code to see the maze generation in action. If everything is working properly, each run with the same seed should produce identical mazes, while using no seed will result in a different maze each time.

Here's my pseudo code for the __break_walls_r method:

1. Mark the current cell as visited
2. In an infinite loop:
   1. Create a new empty list to hold the i and j values you will need to visit
   2. Check the cells that are directly adjacent to the current cell. Keep track of any that have not been visited as "possible directions" to move to
   3. If there are zero directions you can go from the current cell, then draw the current cell and return to break out of the loop
   4. Otherwise, pick a random direction.
   5. Knock down the walls between the current cell and the chosen cell.
   6. Move to the chosen cell by recursively calling _break_walls_r