写出下面程序段的输出结果。def ModifyVal(x,y):z=xx=yy=zdef ModifyListElement(ls,idx,val):ls[idx]=vala,b=3,5print(a,b)ModifyVal(a,b)print(a,b)c=[7,8,9]print(c)ModifyListElement(c,1,6)print(c)答：运行结果为：