code: public function collect(Traversable $iterator)
      {
          $this->deprecations = array();
  
          set_error_handler(array($this, 'errorHandler'));
  
          foreach ($iterator as $name => $contents) {
              try {
                  $this->twig->parse($this->twig->tokenize(new Twig_Source($contents, $name)));
              } catch (Twig_Error_Syntax $e) {
                  // ignore templates containing syntax errors
              }
          }
  
          restore_error_handler();
  
          $deprecations = $this->deprecations;
          $this->deprecations = array();
  
          return $deprecations;
      }
docs: Returns deprecations for passed templates.
  
  @param Traversable $iterator An iterator of templates (where keys are template names and values the contents of the template)
  
  @return array An array of deprecations