code: def _coerce_list_of_str(obj):
      """Coerce obj to list of str."""
      if obj is None:
          return []
      elif isinstance(obj, str):
          return [obj]
      elif isinstance(obj, list):
          return obj
  
imports: import pkgutil
  import re
  from importlib import import_module
  import pytest
  from sktime.registry import all_estimators
  from sktime.tests._config import EXCLUDE_ESTIMATORS
  from sktime.utils._testing.scenarios_getter import retrieve_scenarios
  from sktime.utils.validation._dependencies import _check_python_version, _check_soft_dependencies
label_desc: Use image node_id 8 for calling a global function with example usage: _coerce_list_of_str(obj) and returns: list, list, obj