class_docstr: Modified version of the CliffWalking environment from Farama-Foundation's
  Gymnasium with walls instead of a cliff.
  
  ### Description
  The board is a 4x12 matrix, with (using NumPy matrix indexing):
  - [3, 0] or obs==36 as the start at bottom-left
  - [3, 11] or obs==47 as the goal at bottom-right
  - [3, 1..10] or obs==37...46 as the cliff at bottom-center
  
  An episode terminates when the agent reaches the goal.
  
  ### Actions
  There are 4 discrete deterministic actions:
  - 0: move up
  - 1: move right
  - 2: move down
  - 3: move left
  You can also use the constants ACTION_UP, ACTION_RIGHT, ... defined above.
  
  ### Observations
  There are 3x12 + 2 possible states, not including the walls. If an action
  would move an agent into one of the walls, it simply stays in the same position.
  
  ### Reward
  Each time step incurs -1 reward, except reaching the goal which gives +10 reward.
code: def reset(self, *, seed=None, options=None):
      self.position = 36
      return self.position, {}
  
imports: import gymnasium
  from gymnasium import spaces
label_desc: Use image node_id 2 for calling the CliffWalkingWallEnv obj's underlying member method code with example usage: obj.reset() and returns: self,  dict