private function getArticleMap(string $sourceLanguage, string $targetLanguage): ArticleMap
    {
        if (!array_key_exists($key = $sourceLanguage . '->' . $targetLanguage, $this->articleMaps)) {
            return $this->articleMaps[$key] = new ArticleMap(
                $this->getPageMap($sourceLanguage, $targetLanguage),
                $this->logger
            );
        }

        return $this->articleMaps[$key];
    }
private function getArticleMap(string $sourceLanguage, string $targetLanguage): ArticleMap
    {
        if (!array_key_exists($key = $sourceLanguage . '->' . $targetLanguage, $this->articleMaps)) {
            return $this->articleMaps[$key] = new ArticleMap(
                $this->getPageMap($sourceLanguage, $targetLanguage),
                $this->logger
            );
        }

        return $this->articleMaps[$key];
    }
private function getArticleMap ( string $ sourceLanguage , string $ targetLanguage ) : ArticleMap { if ( ! array_key_exists ( $ key = $ sourceLanguage . '->' . $ targetLanguage , $ this -> articleMaps ) ) { return $ this -> articleMaps [ $ key ] = new ArticleMap ( $ this -> getPageMap ( $ sourceLanguage , $ targetLanguage ) , $ this -> logger ) ; } return $ this -> articleMaps [ $ key ] ; }
Retrieve article map.

@param string $sourceLanguage The source language.
@param string $targetLanguage The target language.

@return ArticleMap
Retrieve article map .