We use the structure of branches to match subcommands from our previous examples:

match matches.subcommand() {
    (CMD_ADD, Some(matches)) => {
        let token = matches.value_of("TOKEN").unwrap();
        let uid = matches.value_of("UID").unwrap();
        add_session(&conn, token, uid)?;
    }
    (CMD_REMOVE, Some(matches)) => {
        let token = matches.value_of("TOKEN").unwrap();
        remove_session(&conn, token)?;
    }
    (CMD_LIST, _) => {
        println!("LIST");
        let sessions = list_sessions(&conn)?;
        for (token, uid) in sessions {
            println!("Token: {:20}   Uid: {:20}", token, uid);
        }
    }
    _ => { matches.usage(); }
}

For the add subcommand, we extract the TOKEN and UID values from arguments and pass them to the add_session function with a reference to a Connector. For the remove subcommand, we extract only the TOKEN value and call the remove_session function with its corresponding parameters. For the list subcommand, we call the list_session function as is, because we don't need any extra parameters to get all values from a map. This returns a vector of pairs. The first item of the pair contains token, and the second contains uid. We print the values using a fixed width specifier of {:20}.