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: add_assign_like.rs
    path of file: ./repos/derive_more/impl/src
    
    the code of the file until where you have to start completion: use crate::add_helpers::{struct_exprs, tuple_exprs};
use crate::utils::{add_extra_ty_param_bound_op, named_to_vec, unnamed_to_vec};
use proc_macro2::TokenStream;
use quote::{format_ident, quote};
use syn::{Data, DeriveInput, Fields};

pub fn expand(input: &DeriveInput, trait_name: &str) -> TokenStream {
    let trait_ident = format_ident!("{trait_name}");
    let method_name = trait_name.trim_end_matches("Assign").to_lowercase();
    let method_ident = format_ident!("{method_name}_assign");
    let input_type = &input.ident;

    let generics = add_extra_ty_param_bound_op(&input.generics, &trait_ident);
    let (impl_generics, ty_generics, where_clause) = generics.split_for_impl();

    let exprs = match input.data {
        Data::Struct(ref data_struct) => match data_struct.fields {
            Fiel
    
pub fn expand(input: &DeriveInput, trait_name: &str) -> TokenStream {
    let trait_ident = format_ident!("{trait_name}");
    let method_name = trait_name.trim_end_matches("Assign").to_lowercase();
    let method_ident = format_ident!("{method_name}_assign");
    let input_type = &input.ident;

    let generics = add_extra_ty_param_bound_op(&input.generics, &trait_ident);
    let (impl_generics, ty_generics, where_clause) = generics.split_for_impl();

    let exprs = match input.data {
        Data::Struct(ref data_struct) => match data_struct.fields {
            Fields::Unnamed(ref fields) => {
                tuple_exprs(&unnamed_to_vec(fields), &method_ident)
            }
            Fields::Named(ref fields) => {
                struct_exprs(&named_to_vec(fields), &method_ident)
            }
            _ => panic!("Unit structs cannot use derive({trait_name})"),
        },

        _ => panic!("Only structs can use derive({trait_name})"),
    };

    quote! {
        #[automatically_derived]
        impl #impl_generics ::derive_more::#trait_ident for #input_type #ty_generics #where_clause {
            #[inline]
            fn #method_ident(&mut self, rhs: #input_type #ty_generics) {
                #( #exprs; )*
            }
        }
    }
}