protected function getContentPartNumber(): string
    {
        $partNumber = $this->getPartNumber();
        if (0 === \count($this->getParts())) {
            $partNumber .= '.1';
        }

        return $partNumber;
    }
protected function getContentPartNumber(): string
    {
        $partNumber = $this->getPartNumber();
        if (0 === \count($this->getParts())) {
            $partNumber .= '.1';
        }

        return $partNumber;
    }
protected function getContentPartNumber ( ) : string { $ partNumber = $ this -> getPartNumber ( ) ; if ( 0 === \ count ( $ this -> getParts ( ) ) ) { $ partNumber .= '.1' ; } return $ partNumber ; }
Get content part number.

@return string
Get content part number .