WP-CLI command in plugin

gistfile1.php

<?php

/*
Plugin Name: PMC Tag Scrubber
Plugin URI: http://www.pmc.com
Description: Download a .csv of tags/categories with their respective post counts. Flags duplicates automatically.
Author: Taylor Lovett, PMC, 10up
Version: 1.5
Author URI: http://www.10up.com
*/

if ( defined('WP_CLI') && WP_CLI ) {
    
    class Example_Command extends WP_CLI_Command {
        /**
         * Example subcommand
         *
         * @param array $args
         */
        function hello( $args = array() ) {
            // Print a success message
            WP_CLI::success( 'Hello world!' );
        }
        static function help() {
            WP_CLI::line( 'usage: wp example hello' );
        }
    }
    // Register the class as the 'example' command handler
    WP_CLI::add_command( 'example', 'Example_Command' );
    
}