protected function pbCheck( $copyright_file ) {
		$result = $this->getZipContent( $copyright_file );

		foreach ( $result->body->div->div->p as $node ) {

			if ( strpos( $node->a['href'][0], 'pressbooks.com', 0 ) ) {
				$this->isPbEpub = true;
			}
		}
		// applies to PB generated EPUBs with PB_SECRET_SAUCE
		// @see createCopyright() in export/epub/class-pb-epub201.php
		if ( 'copyright-page' === $result->body->div[0]->attributes()->id[0] && 'ugc' === $result->body->div->div->attributes()->class[0] ) {
			$this->isPbEpub = true;
		}
	}
protected function pbCheck( $copyright_file ) {
		$result = $this->getZipContent( $copyright_file );

		foreach ( $result->body->div->div->p as $node ) {

			if ( strpos( $node->a['href'][0], 'pressbooks.com', 0 ) ) {
				$this->isPbEpub = true;
			}
		}
		// applies to PB generated EPUBs with PB_SECRET_SAUCE
		// @see createCopyright() in export/epub/class-pb-epub201.php
		if ( 'copyright-page' === $result->body->div[0]->attributes()->id[0] && 'ugc' === $result->body->div->div->attributes()->class[0] ) {
			$this->isPbEpub = true;
		}
	}
protected function pbCheck ( $ copyright_file ) { $ result = $ this -> getZipContent ( $ copyright_file ) ; foreach ( $ result -> body -> div -> div -> p as $ node ) { if ( strpos ( $ node -> a [ 'href' ] [ 0 ] , 'pressbooks.com' , 0 ) ) { $ this -> isPbEpub = true ; } } // applies to PB generated EPUBs with PB_SECRET_SAUCE // @see createCopyright() in export/epub/class-pb-epub201.php if ( 'copyright-page' === $ result -> body -> div [ 0 ] -> attributes ( ) -> id [ 0 ] && 'ugc' === $ result -> body -> div -> div -> attributes ( ) -> class [ 0 ] ) { $ this -> isPbEpub = true ; } }
Is it an EPUB generated by PB?

@param string $copyright_file

@return boolean
@see createCopyright() in /export/epub/class-pb-epub201.php
Is it an EPUB generated by PB?