None is a null value or no value at all. Assigning None to an item in the 2d-list - clouds, will remove the cloud from the list, thus creating an empty spot.
First appear on: challenge 131
None is a null value or no value at all. Assigning None to an item in the 2d-list - clouds, will remove the cloud from the list, thus creating an empty spot.
First appear on: challenge 131