code: def test_read_eval_data_source(self):
      data = list(self.data.eval)
      self.assertEqual(0, len(data))
  
imports: import unittest
  from typing import List
  from pytext.data.sources.data_source import SafeFileWrapper
  from pytext.data.sources.tsv import BlockShardedTSVDataSource, SessionTSVDataSource, TSVDataSource
  from pytext.utils.test import import_tests_module
label_desc: Use image node_id 7 for calling the TSVDataSourceTest obj's underlying member method code with example usage: obj.test_read_eval_data_source() without return types