pub fn latest_root_hash(&self) -> ValueHash {
        let root_hash = self
            .latest_version()
            .and_then(|version| self.root_hash(version));
        root_hash.unwrap_or_else(|| self.hasher.empty_tree_hash())
    }
Returns the root hash for the latest version of the tree.
core/lib/merkle_tree/src/lib.rs