code: def setUp(self):
      # The super class creates a self.instances field and populates it with some instances with
      # TextFields.
      super(EpochTrackingBucketIteratorTest, self).setUp()
      self.iterator = EpochTrackingBucketIterator(
          sorting_keys=[["text", "num_tokens"]]
      )
      # We'll add more to create a second dataset.
      self.more_instances = [
          self.create_instance(["this", "is", "a", "sentence"]),
          self.create_instance(
              ["this", "is", "in", "the", "second", "dataset"]
          ),
          self.create_instance(["so", "is", "this", "one"]),
      ]
  
imports: from __future__ import absolute_import
  from allennlp.data.iterators import EpochTrackingBucketIterator
  from allennlp.tests.data.iterators.basic_iterator_test import IteratorTest
label_desc: Use image node_id 1 for calling the EpochTrackingBucketIteratorTest obj's underlying member method code with example usage: obj.setUp() without return types