code: def _get_bad_return_tags():
      """Get return_tags arguments that should throw an exception."""
      # case not a str or a list:
      is_int = [12]
      # case is a list, but not all elements are str:
      is_not_all_str = [["this", "is", "a", "test", 12, "!"]]
  
      return is_int + is_not_all_str
  
file_path: sktime/sktime/registry/tests/test_lookup.py
imports: import pytest
  from sktime.base import BaseObject
  from sktime.registry import all_estimators, all_tags, scitype
  from sktime.registry._base_classes import BASE_CLASS_LOOKUP, BASE_CLASS_SCITYPE_LIST, TRANSFORMER_MIXIN_SCITYPE_LIST
  from sktime.registry._lookup import _check_estimator_types
label_desc: Use image node_id 9 for calling a global function with example usage: _get_bad_return_tags() and returns: unknown