wordpress: Filter on post types with custom taxonomy in admin

gistfile1.php

<?php
//Add this to functions PHP

function pippin_add_taxonomy_filters() {
        global $typenow;
 
        // an array of all the taxonomyies you want to display. Use the taxonomy name or slug
        $taxonomies = array('product-category');
 
        // must set this to the post type you want the filter(s) displayed on
        if( $typenow == 'products' ){
 
                foreach ($taxonomies as $tax_slug) {
                        $tax_obj = get_taxonomy($tax_slug);
                        $tax_name = $tax_obj->labels->name;
                        $terms = get_terms($tax_slug);
                        if(count($terms) > 0) {
                                echo "<select name='$tax_slug' id='$tax_slug' class='postform'>";
                                echo "<option value=''>Show All $tax_name</option>";
                                foreach ($terms as $term) { 
                                        echo '<option value='. $term->slug, $_GET[$tax_slug] == $term->slug ? ' selected="selected"' : '','>' . $term->name .' (' . $term->count .')</option>'; 
                                }
                                echo "</select>";
                        }
                }
        }
}
add_action( 'restrict_manage_posts', 'pippin_add_taxonomy_filters' );