code: def test_from_file(self):
      vocabulary_file = self._createVocabFile(
          "test.txt", ("one", "two", "three")
      )
      ds = reader_ops.TextLineDataset(vocabulary_file)
      ds = ds.enumerate(start=1)
      init = lookup_ops.DatasetInitializer(ds)
      table = self.getHashTable()(init, default_value="")
      self.initialize_table(table)
  
      output = table.lookup(
          constant_op.constant([2, 3, 4], dtypes.int64)
      )
      result = self.evaluate(output)
      self.assertAllEqual(["two", "three", ""], result)
  
imports: import os
  from tensorflow.python import tf2
  from tensorflow.python.data.experimental.ops import lookup_ops
  from tensorflow.python.data.ops import dataset_ops
  from tensorflow.python.data.ops import readers
  from tensorflow.python.framework import constant_op
  from tensorflow.python.framework import dtypes
  from tensorflow.python.framework import ops
  from tensorflow.python.ops import lookup_ops
  from tensorflow.python.ops import string_ops
  from tensorflow.python.ops import variables
  from tensorflow.python.platform import test
label_desc: Use image node_id 6 for calling the DatasetInitializerTest obj's underlying member method code with example usage: obj.test_from_file() without return types