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: version.rs
    path of file: ./repos/fluvio/crates/fluvio-package-index/src
    
    the code of the file until where you have to start completion: use semver::Version;
use crate::{TagName, Error};
use std::fmt;

/// A type representing a package version in a PackageId.
///
/// In a PackageId string like `fluvio/fluvio:1.2.3`, this
/// is the `1.2.3`.
///
/// A `PackageVersion` may be either a direct semver, or it may be
/// the name of a tag which can later be re
    
    fn from_str(s: &str) -> Result<Self, Self::Err> {
        // First, try to parse as semver::Version
        if let Ok(version) = Version::parse(s) {
            tracing::debug!("Parsed PackageVersion::Semver from '{}'", s);
            return Ok(Self::Semver(version));
        }

        // Try to parse as TagName
        if let Ok(tagname) = s.parse::<TagName>() {
            tracing::debug!("Parsed PackageVersion::Tag from '{}'", s);
            return Ok(Self::Tag(tagname));
        };

        Err(Error::InvalidPackageVersion(s.to_string()))
    }