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: predicate.rs
    path of file: ./repos/fuels-rs/packages/fuels-code-gen/src/program_bindings/abigen/bindings
    
    the code of the file until where you have to start completion: use fuel_abi_types::abi::full_program::FullProgramABI;
use proc_macro2::{Ident, TokenStream};
use quote::quote;

use crate::{
    error::Result,
    program_bindings::{
        abigen::{
            bindings::{function_generator::FunctionGenerator, utils::extract_main_fn},
            configurables::generate_code_for_configurable_constants,
        },
        generated_code::GeneratedCode,
    },
    utils::{ide
    
fn expand_fn(abi: &FullProgramABI) -> Result<TokenStream> {
    let fun = extract_main_fn(&abi.functions)?;
    let mut generator = FunctionGenerator::new(fun)?;

    let arg_tokens = generator.tokenized_args();

    let body = quote! {
        self.encoder.encode(&#arg_tokens)
    };
    let output_type = quote! {
        ::fuels::types::errors::Result<::fuels::types::unresolved_bytes::UnresolvedBytes>
    };

    generator
        .set_doc("Run the predicate's encode function with the provided arguments".to_string())
        .set_name("encode_data".to_string())
        .set_output_type(output_type)
        .set_body(body);

    Ok(generator.generate())
}