pub fn raw_nodes(&self, keys: &[NodeKey]) -> Vec<Option<RawNode>> {
        let raw_nodes = self.0.db.raw_nodes(keys).into_iter();
        raw_nodes
            .zip(keys)
            .map(|(slice, key)| {
                let slice = slice?;
                Some(if key.is_empty() {
                    RawNode::deserialize_root(&slice)
                } else {
                    RawNode::deserialize(&slice)
                })
            })
            .collect()
    }
Returns raw nodes for the specified `keys`.
core/lib/merkle_tree/src/domain.rs