TokenCountVectorizer give null as result

[oitsuki]

tested via the documentation on latest php-ml

$vectorizer = new TokenCountVectorizer(new WhitespaceTokenizer());

$samples = [
  'Lorem ipsum dolor sit amet dolor',
  'Mauris placerat ipsum dolor',
  'Mauris diam eros fringilla diam',
];

// Build the dictionary.
$vectorizer->fit($samples);

// Transform the provided text samples into a vectorized list.
$test = $vectorizer->transform($samples);

var_dump($test); ===> null