code: public function offsetGet($offset)
      {
          if (!isset($this->data[$offset])) {
              $this->requestAllPages();
          }
          return $this->data[$offset];
      }
docs: Offset to retrieve
  
  @param int|string $offset
  
  @return CanvasObject|null
  
  @see http://php.net/manual/en/arrayaccess.offsetexists.php
  ArrayAccess::offsetGet