// $env->addFunction(new \Twig_SimpleFunction('reverse', function ($theString) {
// return strrev($theString);
// }));
// $env->addExtension(new \My\CustomExtension());
// `{{ foo }}` => `bar`
// $env->addGlobal('foo', 'bar');
// example of enabling the Twig debug mode extension (ex. {{ dump(my_variable) }} to check out the template's available data) -- comment out to disable