Twig use in drupal 7

<?php

require_once(DRUPAL_ROOT . '/sites/all/libraries/Twig/lib/Twig/Autoloader.php');
Twig_Autoloader::register();

function twig_render_string($string, $array)
{
  return ((new Twig_Environment(new Twig_Loader_String()))->render($string, $array));
}

function twig_render_file($file, $array)
{
  $twig = new Twig_Environment(new Twig_Loader_Filesystem(drupal_get_path('theme', 'balance') . '/views'));
  return ($twig->render($file, $array));
}