// hash
Hash my_h=arg0.getHash().copy_my_self();
for(int i=2;i < startAt.size();i++){
Node ap=startAt.getSubNode(i, qt);
Hash your_h=ap.getHash();
ArrayList<Node> kn=your_h.keys_nodes();
int kn_size=kn.size();
for(int j=0;j<kn_size;j++)
my_h.store(kn.get(j),your_h.ref(kn.get(j)).secure());
}
return Node.createHash(my_h);