old_contents: import asyncio
  import functools
  import typing
  from typing import Any, AsyncGenerator, Iterator
  
  try:
      import contextvars  # Python 3.7+ only.
  except ImportError:  # pragma: no cover
      contextvars = None  # type: ignore
  
  
  async def run_in_threadpool(
      func: typing.Callable, *args: typing.Any, **kwargs: typing.Any
  ) -> typing.Any:
      loop = asyncio.get_event_loop()
      if contextvars is not None:  # pragma: no cover
          # Ensure we run in the same context
          child = functools.partial(func, *args, **kwargs)
          context = contextvars.copy_context()
          func = context.run
          args = (child,)
      elif kwargs:  # pragma: no cover
          # loop.run_in_executor doesn't accept 'kwargs', so bind them in here
          func = functools.partial(func, **kwargs)
      return await loop.run_in_executor(None, func, *args)
  
  
  class _StopIteration(Exception):
      pass
  
  
  def _next(iterator: Iterator) -> Any:
      # We can't raise `StopIteration` from within the threadpool iterator
      # and catch it outside that context, so we coerce them into a different
      # exception type.
      try:
          return next(iterator)
      except StopIteration:
          raise _StopIteration
  
  
  async def iterate_in_threadpool(iterator: Iterator) -> AsyncGenerator:
      while True:
          try:
              yield await run_in_threadpool(_next, iterator)
          except _StopIteration:
              break
  
new_contents: import asyncio
  import functools
  import typing
  from typing import Any, AsyncGenerator, Iterator
  
  try:
      import contextvars  # Python 3.7+ only.
  except ImportError:  # pragma: no cover
      contextvars = None  # type: ignore
  
  T = typing.TypeVar("T")
  
  
  async def run_in_threadpool(
      func: typing.Callable[..., T], *args: typing.Any, **kwargs: typing.Any
  ) -> T:
      loop = asyncio.get_event_loop()
      if contextvars is not None:  # pragma: no cover
          # Ensure we run in the same context
          child = functools.partial(func, *args, **kwargs)
          context = contextvars.copy_context()
          func = context.run
          args = (child,)
      elif kwargs:  # pragma: no cover
          # loop.run_in_executor doesn't accept 'kwargs', so bind them in here
          func = functools.partial(func, **kwargs)
      return await loop.run_in_executor(None, func, *args)
  
  
  class _StopIteration(Exception):
      pass
  
  
  def _next(iterator: Iterator) -> Any:
      # We can't raise `StopIteration` from within the threadpool iterator
      # and catch it outside that context, so we coerce them into a different
      # exception type.
      try:
          return next(iterator)
      except StopIteration:
          raise _StopIteration
  
  
  async def iterate_in_threadpool(iterator: Iterator) -> AsyncGenerator:
      while True:
          try:
              yield await run_in_threadpool(_next, iterator)
          except _StopIteration:
              break
  
subject: Add type hint for run_in_threadpool return type