Custom add_menu_page with add_submenu_page admin panel

Custom add_menu_page with add_submenu_page admin panel.php

//Add Custom Admin Menu Item and Sub Menus
function theme_options_panel(){
  add_menu_page('Theme page title', 'Theme menu label', 'manage_options', 'theme-options', 'wps_theme_func');
  add_submenu_page( 'theme-options', 'Settings page title', 'Settings menu label', 'manage_options', 'theme-op-settings', 'wps_theme_func_settings');
  add_submenu_page( 'theme-options', 'FAQ page title', 'FAQ menu label', 'manage_options', 'theme-op-faq', 'wps_theme_func_faq');
}
add_action('admin_menu', 'theme_options_panel');
function wps_theme_func(){
                echo '<div class="wrap"><div id="icon-options-general" class="icon32"><br></div>
                <h2>Theme</h2></div>';
}
function wps_theme_func_settings(){
                echo '<div class="wrap"><div id="icon-options-general" class="icon32"><br></div>
                <h2>Settings</h2></div>';
}
function wps_theme_func_faq(){
                echo '<div class="wrap"><div id="icon-options-general" class="icon32"><br></div>
                <h2>FAQ</h2></div>';
}