code: def test_no_plain_teacher(self):
      from parlai.scripts.display_data import DisplayData
  
      with self.assertRaises(RuntimeError):
          DisplayData.main(task="self_chat")
  
file_path: ParlAI/tests/test_self_chat.py
imports: from tempfile import NamedTemporaryFile
  import unittest
  from parlai.scripts.self_chat import SelfChat
  import parlai.utils.testing
label_desc: Use image node_id 4 for calling the TestSelfChat obj's underlying member method code with example usage: obj.test_no_plain_teacher() without return types