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: ltp.rs
    path of file: ./repos/Symphonia/symphonia-codec-aac/src/aac/ics
    
    the code of the file until where you have to start completion: // Symphonia
// Copyright (c) 2019-2022 The Project Symphonia Developers.
//
// Previous Author: Kostya Shishkov <kostya.shiskov@gmail.com>
//
// This source file includes code originally written for the NihAV
// project. With the author's permission, it has been relicensed for,
// and ported to the Symphonia project.
//
// This Source Code Form is subject to the terms of the Mozilla Public
// License, v. 2.0. If a copy of the MPL was not distributed with this
// file, You can obtain one at https://mozilla.org/MPL/2.0/.

use symphonia_core::errors::{unsupported_error, Result};
use symphonia_core::io::ReadBitsLtr;

#[derive(Clone, Copy)]
pub struct LtpData {}

impl LtpData {
    pub fn read<B: ReadBitsLtr>(bs: &mut B) -> Result<Option<Self>> {
        let predictor_data_present = bs.read_bool()?;

        if !predictor_data_present {
            return Ok(None);
        }

        /*
        if is_main {
            let predictor_re
    
    pub fn read<B: ReadBitsLtr>(bs: &mut B) -> Result<Option<Self>> {
        let predictor_data_present = bs.read_bool()?;

        if !predictor_data_present {
            return Ok(None);
        }

        /*
        if is_main {
            let predictor_reset                         = bs.read_bit()?;
            if predictor_reset {
                let predictor_reset_group_number        = bs.read_bits_leq32(5)?;
            }
            for sfb in 0..max_sfb.min(PRED_SFB_MAX) {
                prediction_used[sfb]                    = bs.read_bit()?;
            }
        }
        else {
            let ltp_data_present                        = bs.read_bit()?;
            if ltp_data_present {
                //ltp data
            }
            if common_window {
                let ltp_data_present                    = bs.read_bit()?;
                if ltp_data_present {
                    //ltp data
                }
            }
        }
        Ok(Some(Self { }))
        */

        unsupported_error("aac: predictor data")
    }