code: public static function templateExists(\Twig_Environment $env, $template) {
          try {
              $env->loadTemplate($template);
          } catch(\Twig_Error_Loader $err) {
              return false;
          } catch(\Twig_Error_Syntax $err) {
              return true;
          }
  
          return true;
      }
docs: @internal
  
  Check if template path is valid (template exists).
  
  @param \Twig_Environment $env      Twig environment
  @param string            $template Template path
  
  @return bool