PHPePub\Core\EPub::addCustomPrefix PHP Method

    function addCustomPrefix($name, $URI)
    {
        if ($this->isFinalized) {
            return;
        }
        $this->opf->addPrefix($name, $URI);
    }

 /**
  * Add iBooks prefix to the ePub book
  *
  * @param EPub $book
  */
 public static function addPrefix($book)
 {
     if (!$book->isEPubVersion2()) {
         $book->addCustomPrefix(self::RENDITION_PREFIX_NAME, self::RENDITION_PREFIX_URI);
     }
 }