from directshowbaseShowBase import ShowBasefrom panda3dcore import CollisionTraverser CollisionNode CollisionHandlerQueue CollisionRayclass MyAppShowBase def __init__self ShowBase__init__sel

You need to import the CollisionSphere class from panda3d.core:

from panda3d.core import CollisionTraverser, CollisionNode, CollisionHandlerQueue, CollisionRay, CollisionSphere