code: def test_lazy(self):
      reader = LazyDatasetReader(self.instances, lazy=True)
      assert reader.num_reads == 0
  
      instances = reader.read("path/to/file")
  
      for _ in range(10):
          _instances = (i for i in instances)
          assert ensure_list(_instances) == self.instances
  
      assert reader.num_reads == 10
  
file_path: magnitude/pymagnitude/third_party/allennlp/tests/data/dataset_readers/lazy_dataset_reader_test.py
imports: from __future__ import absolute_import
  from allennlp.data.fields import TextField
  from allennlp.data.instance import Instance
  from allennlp.data.dataset_readers import DatasetReader
  from allennlp.data.token_indexers import SingleIdTokenIndexer
  from allennlp.data.tokenizers import Token
  from allennlp.common.testing import AllenNlpTestCase
  from allennlp.common.util import ensure_list
label_desc: Use image node_id 2 for calling the TestLazyDatasetReader obj's underlying member method code with example usage: obj.test_lazy() without return types