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: lib.rs
    path of file: ./repos/solana/install/src
    
    the code of the file until where you have to start completion: #![allow(clippy::arithmetic_side_effects)]
#[macro_use]
extern crate lazy_static;

use {
    clap::{crate_description, crate_name, App, AppSettings, Arg, ArgMatches, SubCommand},
    solana_clap_utils::{
        input_parsers::pubkey_of,
        input_validators::{is_pubkey, is_url},
    },
};

mod build_env;
mod command;
mod config;
mod defaults;
mod stop_process;
mod update_manifest;

pub fn is_semver(semver: &str) -> Result<(), String> {
    match semver::Version::parse(semver) {
        Ok(_) => Ok(()),
        Err(err) => Err(format!("{err:?}")),
    }
}

pub fn is_release_channel(channel: &str) -> Result<(), String> {
    match channel {
        "edge" | "beta" | "stable" => Ok(()),
        _ => Err(format!("Invalid release channel {channel}")),
    }
}

pub fn is_explicit_release(string: String) -> Result<(), String> {
    if string.starts_with('v') && is_semver(string.split_at(1).1).is_ok() {
        return Ok(());
    }
    is_semver(&string).or_else(|_| is_release_channel(&string))
}

pub fn explicit_release_of(
    matches: &ArgMatches<'_>,
    name: &str,
) -> Option<config::ExplicitRelease> {
    matches
        .value_of(name)
        .map(ToString::to_string)
        .map(|explicit_release| {
            if explicit_release.starts_with('v')
                && is_semver(explicit_release.split_at(1).1).is_ok()
            {
                config::ExplicitRelease::Semver(explicit_release.split_at(1).1.to_string())
            } else if is_semver(&explicit_release).is_ok() {
                config::ExplicitRelease::Semver(explicit_release)
            } else {
                config::Exp
    
pub fn main_init() -> Result<(), String> {
    solana_logger::setup();

    let matches = App::new("solana-install-init")
        .about("Initializes a new installation")
        .version(solana_version::version!())
        .arg({
            let arg = Arg::with_name("config_file")
                .short("c")
                .long("config")
                .value_name("PATH")
                .takes_value(true)
                .help("Configuration file to use");
            match *defaults::CONFIG_FILE {
                Some(ref config_file) => arg.default_value(config_file),
                None => arg.required(true),
            }
        })
        .arg({
            let arg = Arg::with_name("data_dir")
                .short("d")
                .long("data-dir")
                .value_name("PATH")
                .takes_value(true)
                .required(true)
                .help("Directory to store install data");
            match *defaults::DATA_DIR {
                Some(ref data_dir) => arg.default_value(data_dir),
                None => arg,
            }
        })
        .arg(
            Arg::with_name("json_rpc_url")
                .short("u")
                .long("url")
                .value_name("URL")
                .takes_value(true)
                .default_value(defaults::JSON_RPC_URL)
                .validator(is_url)
                .help("JSON RPC URL for the solana cluster"),
        )
        .arg(
            Arg::with_name("no_modify_path")
                .long("no-modify-path")
                .help("Don't configure the PATH environment variable"),
        )
        .arg(
            Arg::with_name("update_manifest_pubkey")
                .short("p")
                .long("pubkey")
                .value_name("PUBKEY")
                .takes_value(true)
                .validator(is_pubkey)
                .help("Public key of the update manifest"),
        )
        .arg(
            Arg::with_name("explicit_release")
                .value_name("release")
                .index(1)
                .conflicts_with_all(&["json_rpc_url", "update_manifest_pubkey"])
                .validator(is_explicit_release)
                .help("The release version or channel to install"),
        )
        .get_matches();

    let config_file = matches.value_of("config_file").unwrap();
    handle_init(&matches, config_file)
}