code: def test_example_iterator(self):
      iterator = med_mentions_example_iterator(self.med_mentions)
      for example in iterator:
          assert example.text == example.title + " " + example.abstract
  
          for entity in example.entities:
              assert entity.start < entity.end
              assert entity.start < len(example.text)
              assert entity.end < len(example.text)
              assert (
                  entity.mention_text
                  == example.text[entity.start : entity.end]
              )
  
file_path: scispacy/tests/test_data_util.py
imports: import os
  import unittest
  import shutil
  from scispacy.data_util import read_full_med_mentions, med_mentions_example_iterator, remove_overlapping_entities
  from scispacy.data_util import read_ner_from_tsv
label_desc: Use image node_id 3 for calling the TestDataUtil obj's underlying member method code with example usage: obj.test_example_iterator() without return types