code: def test_loop_in_config(self):
      experiment1 = {
          "item1": {"item": "$item2"},
          "item2": {"item": "$item3"},
          "item3": {
              "item": "$item1",
          },
      }
  
      experiment2 = {"item": {"key": [{"key": "$item"}]}}
  
      self.assertRaises(
          LoopInConfigError, lambda: ExperimentConfig(experiment1)
      )
      self.assertRaises(
          LoopInConfigError, lambda: ExperimentConfig(experiment2)
      )
  
imports: import unittest
  from pathlib import Path
  from typing import Any, Dict, List
  from transfer_nlp.plugins.config import CallableInstantiationError, ExperimentConfig, LoopInConfigError, UnknownPluginException, UnknownReferenceError, register_plugin
label_desc: Use image node_id 23 for calling the RegistryTest obj's underlying member method code with example usage: obj.test_loop_in_config() without return types