threading.Thread.start should return self

I often write code like:

threads = []
for i in range(10):
  thread = threading.Thread(target=fn, args=(i,))
  thread.start()
  threads.append(thread)

for t in threads:
  t.join()

and would really prefer:

threads = [threading.Thread(target=fn, args=(i,)).start() for i in range(10)]

Is there a reason why start doesn't return self here: https://github.com/python/cpython/blob/3.10/Lib/threading.py#L940 ?

An alternative would be to add a start: bool = False param to the Thread constructor such that you can construct it with start=True. I'm not sure why you'd ever want to construct a Thread but not start it, so I wish that could default to true, but clearly it can't due to backwards compatibility.

Start at Lib/threading.py around Thread.start, referenced near line 940, and compare the requested return behavior with the constructor alternative in the issue. Done means resolving the API design and documenting the resulting behavior without breaking existing Thread usage.