How to Hide Diagnostic Tool Admin Menus

function plt_hide_diagnostic_tool_menus() {
	//Hide "Diagnostic Tool".
	remove_menu_page('diagnostic-tooloverview');
	//Hide "Diagnostic Tool → Diagnostic Tool".
	remove_submenu_page('diagnostic-tooloverview', 'diagnostic-tooloverview');
	//Hide "Diagnostic Tool → Altered Files".
	remove_submenu_page('diagnostic-tooloverview', 'diagnostic-tool/views/dtfilechecksumview.php');
	//Hide "Diagnostic Tool → Email Testing".
	remove_submenu_page('diagnostic-tooloverview', 'diagnostic-tool/views/dtemailview.php');
	//Hide "Diagnostic Tool → Outbound Connections".
	remove_submenu_page('diagnostic-tooloverview', 'diagnostic-tool/views/dtoutboundconnectionsview.php');
	//Hide "Diagnostic Tool → Untracked Transports".
	remove_submenu_page('diagnostic-tooloverview', 'diagnostic-tool/views/dtoutboundconnectionsuntrackedview.php');
	//Hide "Diagnostic Tool → DNS Resolver".
	remove_submenu_page('diagnostic-tooloverview', 'diagnostic-tool/views/dtresolverview.php');
	//Hide "Diagnostic Tool → Cron Overview".
	remove_submenu_page('diagnostic-tooloverview', 'diagnostic-tool/views/dtcronview.php');
	//Hide "Diagnostic Tool → Settings".
	remove_submenu_page('diagnostic-tooloverview', 'diagnostic-tool/views/dtsettings.php');
}

add_action('admin_menu', 'plt_hide_diagnostic_tool_menus', 11);

Where do I put this code?