Where did "ob" come from?
Is that just a (random) name that is assigned to the objects in the list or is "ob" a part of the Python programming language?
Just watched this video, it's definitely a bit confusing if you're new to programming. The "ob" he uses when he writes "for ob in obs" is an arbitrary name he chose - it could be anything, e.g. "for my_cubes in obs". If you did change it to "my_cubes", you'd just have to make sure to refer to "my_cubes" instead of "ob" within the loop (e.g. "my_cubes.location.z = sin(my_cubes.location.x)")