set extens point object handl collect extens point handl us handl extend todo us minim updat strategi instead remov ad tfm collect extens point ep model facad extens point handl ep collect extens point ext pt arrai list extens point ep extens point ep ext pt remov extens point handl ep object ep extens point add extens point handl ep illeg argument except handl handl extens point extens point 