How to Hide the "WPRaiz Content API" Admin Menu

function plt_hide_wpraiz_content_api_tool_menus() {
	//Hide the "Tools → WPRaiz Content API" menu.
	remove_submenu_page('tools.php', 'wpraiz-content-api');
}

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

Where do I put this code?