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: mod.rs
    path of file: ./repos/some-tank-game-rs/src/persister
    
    the code of the file until where you have to start completion: use std::collections::VecDeque;
use bevy::{ecs::{component::Component, system::CommandQueue}, prelude::*, reflect::{TypeRegistry, serde::ReflectSerializer}};
use serde::{Serialize};
use serde_json::Value;
use crate::GamePiece;

mod state;
pub use state::*;

pub enum PersisterCommand {
    SaveState,
    Loa
    
fn _serialize<T:Serialize + Component>(world:&mut World) -> serde_json::Value {

    let mut array:Vec<Value> = Vec::default();
    for (t, _) in world.query::<(&T, &GamePiece)>().iter(world) {
        let value = serde_json::to_value(t).unwrap();
        println!("{:?}", value);
        array.push(value);
    }

    serde_json::Value::Array(array)
}