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: extension.rs
    path of file: ./repos/ouch/src
    
    the code of the file until where you have to start completion: //! Our representation of all the supported compression formats.

use std::{ffi::OsStr, fmt, path::Path};

use bstr::ByteSlice;

use self::CompressionFormat::*;
use crate::{error::Error, warning};

pub const SUPPORTED_EXTENSIONS: &[&str] = &[
 
    
pub fn parse_format(fmt: &OsStr) -> crate::Result<Vec<Extension>> {
    let fmt = <[u8] as ByteSlice>::from_os_str(fmt).ok_or_else(|| Error::InvalidFormat {
        reason: "Invalid UTF-8".into(),
    })?;

    let mut extensions = Vec::new();
    for extension in fmt.split_str(b".") {
        let extension = to_extension(extension).ok_or_else(|| Error::InvalidFormat {
            reason: format!("Unsupported extension: {}", extension.to_str_lossy()),
        })?;
        extensions.push(extension);
    }

    Ok(extensions)
}