code: def test_safe_personas(self):
      base_kwargs = Opt(
          {"datatype": "train", "task": "blended_skill_talk"}
      )
      safe_personas_only_to_count = {False: 4819, True: 3890}
      for (
          safe_personas_only,
          count,
      ) in safe_personas_only_to_count.items():
          full_kwargs = {
              **base_kwargs,
              "safe_personas_only": safe_personas_only,
          }
          parser = setup_args()
          parser.set_defaults(**full_kwargs)
          opt = parser.parse_args([])
          personas = _load_personas(opt)
          self.assertEqual(len(personas), count)
  
imports: import unittest
  from unittest.mock import patch
  import parlai.utils.testing
  from parlai.agents.repeat_label.repeat_label import RepeatLabelAgent
  from parlai.core.opt import Opt
  from parlai.core.params import ParlaiParser
  from parlai.core.worlds import create_task
  from parlai.scripts.display_data import setup_args
  from parlai.tasks.blended_skill_talk.agents import ContextGenerator
  from parlai.tasks.blended_skill_talk.worlds import InteractiveWorld, _load_personas
label_desc: Use image node_id 2 for calling the TestBlendedSkillTalkInteractiveWorld obj's underlying member method code with example usage: obj.test_safe_personas() without return types