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: persist.rs
    path of file: ./repos/nih-plug/nih_plug_derive/tests
    
    the code of the file until where you have to start completion: use std::collections::BTreeMap;
use std::sync::Mutex;

use nih_plug::prelude::*;

#[derive(Params, Default)]
struct WrapperParams {
    #[nested(id_prefix = "foo")]
    pub inner: InnerParams,
}

#[derive(Params, Default)]
struct ArrayWrapperParams {
    #[nested(array)]
    pub inners: [InnerParams; 3],
}

#[derive(Default)]
struct InnerParams {
    /// The value `deserialize()` has been called with so we can check that the prefix has been
    /// stripped correctly.
    pub deserialize_called_with: Mutex<Option<BTreeMap<String, String>>>,
}


    
        fn deserialize() {
            let mut serialized = BTreeMap::new();
            serialized.insert(String::from("bar_1"), String::from("aaa"));
            serialized.insert(String::from("bar_2"), String::from("bbb"));
            serialized.insert(String::from("bar_3"), String::from("ccc"));

            let params = ArrayWrapperParams::default();
            params.deserialize_fields(&serialized);
            for (inner, expected_value) in params.inners.into_iter().zip(["aaa", "bbb", "ccc"]) {
                let deserialized = inner
                    .deserialize_called_with
                    .lock()
                    .unwrap()
                    .take()
                    .unwrap();
                assert_eq!(deserialized.len(), 1);
                assert_eq!(deserialized["bar"], expected_value);
            }
        }