FileType::purify

public function purify(): self
{
	$folderId = $this->getFilterValue('FOLDER_ID', '=@');
	if (is_null($folderId))
	{
		$removeFilterFolderId = true;
		$this->addFilter('FOLDER_ID', null);
	}

	parent::purify();

	if (isset($removeFilterFolderId))
	{
		$this->unsetFilter('FOLDER_ID');
	}

	return $this;
}