in src/tests.rs [163:170]
fn random_sampling(tree: &SMT<P>, idx: &TreeIndex) -> bool {
let secret = &ALL_ZEROS_SECRET;
let proof = RandomSamplingProof::<P>::random_sampling(tree, idx, secret);
let serialized = proof.serialize();
let deserialized = RandomSamplingProof::<P>::deserialize(&serialized).unwrap();
deserialized.verify_random_sampling_proof(&tree.get_root())
}