async version of __init__

async_init.py

import asyncio


class AsyncInit:
    def __await__(self):
        async def _():
            await self.__ainit__()
            return self
        return _().__await__()

    async def __ainit__(self) -> None:
        ...


class AsyncSpam(AsyncInit):
    def __init__(self, value):
        self.value = value
        self.initialized = False

    async def __ainit__(self):
        await asyncio.sleep(1)
        self.initialized = True


async def amain():
    spam = await AsyncSpam('ham')
    assert spam.initialized
    print(spam.value)


asyncio.run(amain())