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: keys.rs
    path of file: ./repos/themis/tests/rust
    
    the code of the file until where you have to start completion: // Copyright 2018 (c) rust-themis developers
//
// Licensed under the Apache License, Version 2.0 (the "License");
// you may not use this file
    
fn parse_generated_symmetric_keys_back() {
    let this_key = SymmetricKey::new();
    let same_key = SymmetricKey::try_from_slice(&this_key);
    assert!(same_key.is_ok());
    let same_key = same_key.unwrap();
    assert_eq!(this_key, same_key);
}