De-compact async with tuple on 3.8-

Turns out can't use the nicer syntax before python 3.9 (even though it
doesn't seem documented anywhere?).

Relates to #207

tests/test_discovery.py

@@ -268,28 +268,30 @@ async def close_chans_before_nursery(
  portal2 = await tn.start_actor(
  'consumer2', enable_modules=[__name__])
 
- async with (
- portal1.open_stream_from(stream_forever) as agen1,
- portal2.open_stream_from(stream_forever) as agen2,
- ):
- async with trio.open_nursery() as n:
- n.start_soon(streamer, agen1)
- n.start_soon(cancel, use_signal, .5)
- try:
- await streamer(agen2)
- finally:
- # Kill the root nursery thus resulting in
- # normal arbiter channel ops to fail during
- # teardown. It doesn't seem like this is
- # reliably triggered by an external SIGINT.
- # tractor.current_actor()._root_nursery.cancel_scope.cancel()
-
- # XXX: THIS IS THE KEY THING that happens
- # **before** exiting the actor nursery block
-
- # also kill off channels cuz why not
- await agen1.aclose()
- await agen2.aclose()
+ # TODO: compact this back as was in last commit once
+ # 3.9+, see https://github.com/goodboy/tractor/issues/207
+ async with portal1.open_stream_from(stream_forever) as agen1:
+ async with portal2.open_stream_from(
+ stream_forever
+ ) as agen2:
+ async with trio.open_nursery() as n:
+ n.start_soon(streamer, agen1)
+ n.start_soon(cancel, use_signal, .5)
+ try:
+ await streamer(agen2)
+ finally:
+ # Kill the root nursery thus resulting in
+ # normal arbiter channel ops to fail during
+ # teardown. It doesn't seem like this is
+ # reliably triggered by an external SIGINT.
+ # tractor.current_actor()._root_nursery.cancel_scope.cancel()
+
+ # XXX: THIS IS THE KEY THING that happens
+ # **before** exiting the actor nursery block
+
+ # also kill off channels cuz why not
+ await agen1.aclose()
+ await agen2.aclose()
  finally:
  with trio.CancelScope(shield=True):
  await trio.sleep(1)

tests/test_pubsub.py

@@ -60,14 +60,13 @@ def pred(i):
  def pred(i):
  return isinstance(i, int)
 
+ # TODO: https://github.com/goodboy/tractor/issues/207
  async with tractor.find_actor(pub_actor_name) as portal:
- async with (
- portal.open_stream_from(
+ async with portal.open_stream_from(
  pubber,
  topics=which,
  seed=seed,
- ) as stream
- ):
+ ) as stream:
  task_status.started(stream)
  times = 10
  count = 0