static private function ngramsAsArray(string $sep, array $ngrams) : array {
        $ngramsArray = array();
        foreach($ngrams as $key => $ngram) {
            $ngramsArray[] = explode($sep, $ngram);
        }
        return $ngramsArray;
    }
static private function ngramsAsArray(string $sep, array $ngrams) : array {
        $ngramsArray = array();
        foreach($ngrams as $key => $ngram) {
            $ngramsArray[] = explode($sep, $ngram);
        }
        return $ngramsArray;
    }
static private function ngramsAsArray ( string $ sep , array $ ngrams ) : array { $ ngramsArray = array ( ) ; foreach ( $ ngrams as $ key => $ ngram ) { $ ngramsArray [ ] = explode ( $ sep , $ ngram ) ; } return $ ngramsArray ; }
Transform the ngram array to an array of their tokens
@param string $sep
@param array $ngrams
@return array $ngramsArray
Transform the ngram array to an array of their tokens