Script repeating `trio.ClosedResourceError`

resource_error_test.py

import trio
from aioresult import ResultCapture
import string


async def task(receiver):
    new_list = []
    list_nums = []
    alpha_nums = []
    async with receiver:
        async for x in receiver:
            if str(x).isdigit():
                list_nums.append(x)
            if str(x).isalpha():
                alpha_nums.append(x)
    for letter in alpha_nums:
        for number in list_nums:
            value = str(letter).join(number)
            new_list.append(value)
    await trio.sleep(0.1)
    return new_list


async def mailer(i, sender):
    async with sender:
        await sender.send(i)


async def send_it(sender):
    letters = string.ascii_letters
    numbers = string.digits
    abc_list = [[x for x in letters].extend([y for y in numbers])]
    async with trio.open_nursery() as send_nurse:
        [send_nurse.start_soon(mailer, i, sender.clone()) for i in abc_list]


async def main():
    sender, receiver = trio.open_memory_channel(1)
    async with trio.open_nursery() as nursery:
        async with sender, receiver:
            nursery.start_soon(send_it, sender)
            return1 = ResultCapture.start_soon(nursery, task, receiver.clone())
    result1 = return1.result()
    print('{0} return type = {1}'.format(result1, type(result1)))


if __name__ == "__main__":
    trio.run(main)
    

Running the script with 39 and 40 swapped, resulted in the execution of the script hanging.

async def main():
    sender, receiver = trio.open_memory_channel(1)
    async with sender, receiver:
        async with trio.open_nursery() as nursery:
            nursery.start_soon(send_it, sender)
            return1 = ResultCapture.start_soon(nursery, task, receiver)
    await trio.sleep(0.1)
    result1 = await return1.result()
    print('{0} return type = {1}'.format(result1, type(result1)))