I can't understand how to use the 'PartitionCellBySketch'

[CNWindson]

Thanks for your video on the Youtube. It helps me a lot. I'm waiting for every new video on Monday 233.
Here 's a problem that I'm trying to make a python script to produce random cylinder from your 3D-RVE script. But when I want to do the 'PartitionCellBySketch', I always got some error. Could u plz give me a detailed explanation？ Thanks a lot.

mdb.models['Model-1'].parts['Wrie'].PartitionCellBySketch(
                 cells=mdb.models['Model-1'].parts['Wrie'].cells.findAt(((0.2, 0.2,0.2),)),
                 sketch=mdb.models['Model-1'].sketches['__profile__'], sketchOrientation=TOP, sketchPlane=
                 mdb.models['Model-1'].parts['Wrie'].datums[dp2.id],
                 sketchUpEdge=mdb.models['Model-1'].parts['Wrie'].edges.findAt((0.0, 0.0, 5.0), ))

There is always something wrong with 'findAt' in 'cells' and 'sketchUpEdge'(how to confige the coordinate and what does it mean?)
And I'll send u an email of my poor py script. It's my honour that if u could give me some help!