The Blender.Scene submodule.
Warning:
scene.objects.new is the preferred way to add new objects to
a scene. The older way is to create an object with
Object.New(), link the data to the new object, then link the
object to the scene. This way is not recommended since a forgotten
step or run-time error in the script can cause bad things to be
done to Blender's database.
If you use this older method, it's recommended to always perform
the operations in this order. This is because if there is no
object data linked to an object ob, scene.link(ob)
will automatically create the missing data. This is OK on its own,
but if after that object ob is linked to obdata, the
automatically created one will be discarded -- as expected -- but
will stay in Blender's memory space until the program is exited,
since Blender doesn't really get rid of most kinds of data. So
first linking ObData to object, then object to scene is a tiny tiny
bit faster than the other way around and also saves some realtime
memory (if many objects are created from scripts, the savings
become important).