Select groups in scene

import maya.cmds as mc
lsT=mc.ls(type="transform")

Group=[]
for i in lsT:
       lsS=mc.listRelatives(i,shapes=1)

       if(not lsS):
               if mc.nodeType(i)!="joint":
                       Group+=[i]
for s in Group:
       mc.select(s,add=1)