Bug in observation vector

[jadaross]

The observation vector only ever returns 0 for the component of the observation space which indicates if a new session was created on drone d.

I believe this bug occurs when the observation vector is created in PettingZooParallelWrapper in the method observation_change which creates the observation vector. From my understanding the flag for a new session being created on drone d would be triggered if the following code block was ever evaluated as True: 'Sessions' in obs[hostname]. However the key 'Sessions' is never added to the observation dictionary and therefore this statement is never True.