class_docstr: Test of DialoGPT model.
docstr: Test RuntimeError is thrown when add_start_token = True and yet add_special_tokens = False
code: def test_start_token(self):
      """
      Test RuntimeError is thrown when add_start_token = True and yet add_special_tokens = False
      """
      with self.assertRaises(RuntimeError):
          create_agent(
              {
                  "model": "hugging_face/dialogpt",
                  "add_special_tokens": False,
                  "add_start_token": True,
              }
          )
  
file_path: ParlAI/tests/nightly/gpu/test_dialogpt.py
imports: import unittest
  import parlai.utils.testing
  from parlai.core.agents import create_agent
label_desc: Use image node_id 3 for calling the TestDialogptModel obj's underlying member method code with example usage: obj.test_start_token() without return types