docstr: Verify that AttrDict implements Mapping, but not built-in Dict
docstr_tok: ["Verify","that","AttrDict","implements","Mapping",",","but","not","built-in","Dict"]
code: def test_attr_dict_is_mapping_but_not_built_in_dict(self):
      """Verify that AttrDict implements Mapping, but not built-in Dict"""
      attr_dict = AttrDict({"x": {"y": "z"}})
      self.assertIsInstance(attr_dict.x, Mapping)
      self.assertIsInstance(attr_dict.x, MappingABC)
      self.assertNotIsInstance(attr_dict.x, MutableMapping)
      self.assertNotIsInstance(attr_dict.x, MutableMappingABC)
      self.assertNotIsInstance(attr_dict.x, dict)
  
imports: import os
  import tempfile
  import unittest
  from collections.abc import Mapping
  from collections.abc import MutableMapping
  from typing import Mapping, MutableMapping
  from unittest.mock import MagicMock, mock_open, patch
  from parameterized import parameterized
  from toml import TomlDecodeError
  from streamlit.runtime.secrets import SECRETS_FILE_LOCS, AttrDict, Secrets
  from tests.exception_capturing_thread import call_on_threads
label_desc: Use image node_id 1 for calling the AttrDictTest obj's underlying member method code with example usage: obj.test_attr_dict_is_mapping_but_not_built_in_dict() without return types