/**
  * Checks if this file is a child of the given filebase
  * directory.
  *
  * @see sfFilebasePlugin::fileLiesWithin
  * @param mixed sfFilebaseDirectory | string $file
  * @return boolean
  */
 public function liesWithin($file)
 {
     return $this->filebase->fileLiesWithin($this, $file);
 }