How to make a menu display in the WordPress sidebar

To make the menu visible in the appearance section we need to write the following code in the functions.php  

function menu_theme_setup() { 

  register_nav_menus( array(  

    'header' => 'Header menu',  

    'footer' => 'Footer menu'  

  ) ); 

} 

add_action( 'after_setup_theme', 'menu_theme_setup' ); 

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