How do I create a script from python to add items in to blender game engine.

Hi,

I’m new to python and blender. I’ve been experimenting with python timer creating a count down timer using a python script.

Here is my question how do add a pre-defined object in blender, a sphere into the game engine while it is running via an external script. Which works with the use of a count down timer that randomly adds item to the field with in the given time frame.