code: public function fetchOffset($num)
      {
          // If the content has been modified, regenerate $this->content.
          // and $this->contentKeys.
          if ($this->contentModified) {
              $this->generateContent();
          }
          
          // If the offset exists, return the data.
          $key = $this->fetchOffsetKey($num);
          if ($key != null) {
              return $this->content[$key];
          }
          
          return null;
      }
docs: Returns a resource by numerical offset.
  
  @param num A number.