Function sp_trie::delta_trie_root

pub fn delta_trie_root<L: TrieConfiguration, I, A, B, DB>(
    db: &mut DB, 
    root: TrieHash<L>, 
    delta: I
) -> Result<TrieHash<L>, Box<TrieError<L>>> where
    I: IntoIterator<Item = (A, Option<B>)>,
    A: AsRef<[u8]> + Ord,
    B: AsRef<[u8]>,
    DB: HashDB<L::Hash, DBValue>, 

Determine a trie root given a hash DB and delta values.