code: public static function findByPid($intPid, array $arrOptions=array())
  	{
  		$t = static::$strTable;
  
  		// Convert UUIDs to binary
  		if (Validator::isStringUuid($intPid))
  		{
  			$intPid = StringUtil::uuidToBin($intPid);
  		}
  
  		return static::findBy(array("$t.pid=UNHEX(?)"), bin2hex($intPid), $arrOptions);
  	}
docs: Find a file by its parent ID
  
  @param mixed $intPid     The parent ID
  @param array $arrOptions An optional options array
  
  @return Collection|FilesModel[]|FilesModel|null A collection of models or null if there are no files