code: def _run_case_missing_key(self):
      case = TestCase(
          "extrinsic-step-missing-key",
          SP_FLAG + "ExtrinsicHallucinatedStep",
          "",
      )
      parser = StepByStepReason.add_cmdline_args(
          ParlaiParser(False, False), None
      )
      parser.set_defaults(thought_token="", inner_separator_token="")
      opt = parser.parse_args(
          case.flags.split(" ") if len(case.flags) > 0 else []
      )
      steps_reason = StepByStepReason(opt)
      with self.assertRaises(RuntimeError):
          steps_reason.get_full_reason_text({"steps": ["a"]})
  
file_path: ParlAI/tests/tasks/reasoning_teacher/test_step_by_step.py
imports: from typing import List
  import unittest
  from parlai.core.params import ParlaiParser
  from dataclasses import dataclass
label_desc: Use image node_id 3 for calling the TestStepPertubations obj's underlying member method code with example usage: obj._run_case_missing_key() without return types