public function normalize($document);
public function __invoke($data) { foreach ($data as $category => $documents) { foreach ($documents as $index => $document) { if ($this->documentNormalizer) { $document = $this->documentNormalizer->normalize($document); } $tokens = $this->tokenizer->tokenize($document); if ($this->tokenNormalizer) { $tokens = $this->tokenNormalizer->normalize($tokens); } $data[$category][$index] = $tokens; } } return $data; }