Wordpress: Navigation Menu Embed

header.php

<?php
							if(function_exists('wp_nav_menu')):
								wp_nav_menu(
								array(
									'menu' =>'primary_nav',
									'container'=>'',
									'depth' => 2,
									'menu_id' => '' )
								);
							else:
						?>
						<ul id="menu">
							<?php wp_list_pages('title_li=&depth=1'); ?>
						</ul>
						<?php
							endif;
						?>