new_contents: """Tests for the optional typing-extensions dependency."""
  
  import sys
  import types
  import inspect
  import importlib
  
  import typing_extensions
  import numpy.typing as npt
  
  
  def _is_sub_module(obj: object) -> bool:
      """Check if `obj` is a `numpy.typing` submodule."""
      return inspect.ismodule(obj) and obj.__name__.startswith("numpy.typing")
  
  
  def _is_dunder(name: str) -> bool:
      """Check whether `name` is a dunder."""
      return name.startswith("__") and name.endswith("__")
  
  
  def _clear_attr(module: types.ModuleType) -> None:
      """Clear all (non-dunder) module-level attributes."""
      del_names = [name for name in vars(module) if not _is_dunder(name)]
      for name in del_names:
          delattr(module, name)
  
  
  MODULES = {"numpy.typing": npt}
  MODULES.update({
      f"numpy.typing.{k}": v for k, v in vars(npt).items() if _is_sub_module(v)
  })
  
  
  def test_no_typing_extensions() -> None:
      """Import `numpy.typing` in the absence of typing-extensions.
  
      Notes
      -----
      Ideally, we'd just run the normal typing tests in an environment where
      typing-extensions is not installed, but unfortunatelly this is currently
      impossible as it is an indirect hard dependency of pytest.
  
      """
      assert "typing_extensions" in sys.modules
  
      try:
          sys.modules["typing_extensions"] = None
          for name, module in MODULES.items():
              _clear_attr(module)
              assert importlib.reload(module), name
      finally:
          sys.modules["typing_extensions"] = typing_extensions
          for module in MODULES.values():
              _clear_attr(module)
              importlib.reload(module)
  
subject: Test that `numpy.typing` can be imported in the the absence of typing-extensions