I also tried this script
p = mdb.models['Model-1'].parts['sec1']
Face = mdb.models['Model-1'].parts['sec1'].faces.getByBoundingBox(0.53,-0.03,0.0,2.03,-0.03,2.0)
p.PartitionFaceByDatumPlane(datumPlane=mdb.models['Model-1'].parts['sec1'].datums[7], faces=Face)
but I got the same result...