code: def test_block_has_answer(self):
      config = self.get_config()
      retriever = self.get_dummy_retriever()
      tokenizer = retriever.tokenizer
  
      retrieved_block_ids = np.array([0, 3, 5], dtype=np.long)
      question_input_ids = tokenizer(["Test question"]).input_ids
      answer_ids = tokenizer(
          ["the fourth", "longer longer"],
          add_special_tokens=False,
          return_token_type_ids=False,
          return_attention_mask=False,
      ).input_ids
      max_length = config.reader_seq_len
  
      has_answers, start_pos, end_pos, _ = retriever(
          retrieved_block_ids,
          question_input_ids,
          answer_ids=answer_ids,
          max_length=max_length,
          return_tensors="np",
      )
  
      self.assertEqual([False, True, True], has_answers)
      self.assertEqual(
          [[-1, -1, -1], [6, -1, -1], [6, 7, 8]], start_pos
      )
      self.assertEqual([[-1, -1, -1], [7, -1, -1], [7, 8, 9]], end_pos)
  
imports: import os
  import shutil
  import tempfile
  from unittest import TestCase
  from unittest.mock import patch
  import numpy
  from datasets import Dataset
  from transformers.models.realm.configuration_realm import RealmConfig
  from transformers.models.realm.retrieval_realm import _REALM_BLOCK_RECORDS_FILENAME, RealmRetriever
  from transformers.models.realm.tokenization_realm import VOCAB_FILES_NAMES, RealmTokenizer
label_desc: Use image node_id 9 for calling the RealmRetrieverTest obj's underlying member method code with example usage: obj.test_block_has_answer() without return types