You are an expert in writing code in many different languages. Your goal is to perform code completion for the following code, keeping in mind the rest of the code and the file meta data.
    Metadata details:
    filename: merklized.rs
    path of file: ./repos/fuel-core/crates/storage/src/blueprint
    
    the code of the file until where you have to start completion: //! The module defines the `Merklized` blueprint for the storage.
//! The `Merklized` blueprint implements the binary merkle tree on top of the storage
//! for all entries.

use crate::{
    blueprint::{
        Blueprint,
        SupportsBatchi
    
            fn root_returns_error_empty_metadata() {
                let mut storage = InMemoryStorage::default();
                let mut structured_storage = StructuredStorage::new(&mut storage);

                let root = structured_storage
                    .storage_as_mut::<$table>()
                    .root(&$key);
                assert!(root.is_err())
            }