code: public function canHandle(ThingInterface $thing)
      {
          $ok = false;
  
          if ($this->defaults->passIfCategory()) {
              $category = $this->defaults->getCategory();
              if ($category === 'image' && $thing instanceof ImageInterface
                  || $category === 'document' && $thing instanceof DocumentInterface
                  || $category === 'audio' && $thing instanceof AudioInterface
                  || $category === 'video' && $thing instanceof VideoInterface
                  || $category === 'text' && $thing instanceof TextInterface
              ) {
                  $ok = true;
              }
          }
          if ($this->defaults->passIfMime()) {
              $mime = $this->defaults->getMime();
              $ok   = $mime === $thing->getMime();
          }
  
          return $ok;
      }
docs: @param ThingInterface $thing
  
  @return boolean