A generator that can be paused by sending a boolean value.

pausable_generator.py

"""Pausable generator."""

import asyncio

SENTINEL = object()


async def gen():
    active = True

    for n in range(100):

        if not active:
            print('generator paused')
            while True:
                active = (
                    yield SENTINEL
                )
                if active:
                    break
                await asyncio.sleep(1)

        active = (
            yield n
        )


async def main():
    g = gen()
    await g.asend(None)  # prime generator

    for active in (True, True, False, True, True):
        result = await g.asend(active)
        if result is SENTINEL:
            continue
        print('result', result)

if __name__ == '__main__':
    asyncio.run(main())