Function sp_trie::read_child_trie_value_with

pub fn read_child_trie_value_with<L: TrieConfiguration, Q: Query<L::Hash, Item = DBValue>, DB>(
    keyspace: &[u8], 
    db: &DB, 
    root_slice: &[u8], 
    key: &[u8], 
    query: Q
) -> Result<Option<Vec<u8>>, Box<TrieError<L>>> where
    DB: HashDBRef<L::Hash, DBValue>, 

Read a value from the child trie with given query.