class_docstr: Computes ROUGE Scores.
class_docstr_tok: ["Computes","ROUGE","Scores","."]
code: def setup(self):
      if self._use_nltks_recommended_sentence_tokenizer:
          tokenizer_installed = False
  
          if not tokenizer_installed:
              logging.info(_LOGGING_MESSAGE_TOKENIZER_PREPARER)
              nltk.download("punkt")
  
imports: import dataclasses
  from typing import Dict, Iterable, Optional
  from absl import logging
  import apache_beam
  import nltk
  from tensorflow_model_analysis.metrics import metric_types
  from tensorflow_model_analysis.metrics import metric_util
  from tensorflow_model_analysis.proto import config_pb2
  from rouge_score import rouge_scorer
  from rouge_score import scoring
  from rouge_score import tokenizers
label_desc: Use image node_id 2 for calling the RougeCombiner obj's underlying member method code with example usage: obj.setup() without return types