How to run specify multiple steps with --only?

[soredake]

When i run .\topgrade --only powershell,pip3 i get:

error: "powershell,pip3" isn't a valid value for '--only <STEP>...'
        [possible values: am, asdf, atom, bin, brew_cask, brew_formula, bun, cargo, chezmoi, chocolatey, choosenim, composer, conda, config_update, containers, custom_commands, deb_get, deno, distrobox, dkp_pacman, dotnet, emacs, firmware, flatpak, flutter, fossil, gcloud, gem, ghcup, github_cli_extensions, git_repos, gnome_shell_extensions, go, guix, haxelib, helm, home_manager, jetpack, julia, juliaup, kakoune, helix, krew, macports, mamba, mas, micro, myrepos, nix, node, opam, pacdef, pacstall, pearl, pip3, pip_review, pipupgrade, pipx, pkg, pkgin, pnpm, powershell, protonup, raco, rcm, remotes, restarts, rtcl, ruby_gems, rustup, scoop, sdkman, sheldon, shell, snap, sparkle, spicetify, stack, system, tldr, tlmgr, tmux, toolbx, vagrant, vcpkg, vim, winget, wsl, wsl_update, yadm, yarn]

        Did you mean "powershell"?

USAGE:
    topgrade.exe --only <STEP>...

For more information try --help

[SteveLauC]

Multiple steps should be separated with ' ' instead of ',':

$ topgrade --dry-run --only system cargo
── 22:33:16 - System update ────────────────────────────────────────────────────
Dry running: /usr/bin/sudo /usr/bin/dnf upgrade -y

── 22:33:16 - Cargo ────────────────────────────────────────────────────────────
Dry running: /home/steve/.cargo/bin/cargo-install-update install-update --git --all

── 22:33:16 - Summary ──────────────────────────────────────────────────────────
System update: OK
cargo: OK