Auto null

import maya.cmds as mc
obj=[str(o) for o in mc.ls( sl=True,tr=True)]
for i in obj:
name="IFWnull_"+str(i)
objctrl= mc.curve(n=name,d=1,p=[(-1,1,1),(-1,1,-1),(1,1,-1),(1,1,1),(-1,1,1),(-1,-1,1),(-1,-1,-1),(-1,1,-1),(-1,1,1),(-1,-1,1),(1,-1,1),(1,1,1),(1,1,-1),(1,-1,-1),(1,-1,1),(1,-1,-1),(-1,-1,-1),],k=[0,1,2,3,4,5,6,7,8,9,10,11,12,13,14,15,16])
cons= mc.parentConstraint( i, objctrl,mo=False )
mc.delete(cons)
mc.setAttr (name+".overrideEnabled", 1)
mc.setAttr(name+".overrideColor", 30)
mc.select(i)