Using apscheduler with asyncpg db as Job Store: Error MissingGreenlet

I'm trying to use Apscheduler with a postgresql db via an asyncpg connection. I thought it would working, because asyncpg supports sqlalchemy ref. But yeah, it isn't working. And to make it even worst, I don't understand the error message, so I have not even a guess what to google for.

import asyncio
from apscheduler.schedulers.asyncio import AsyncIOScheduler
from apscheduler.jobstores.sqlalchemy import SQLAlchemyJobStore

def simple_job():
    print('This was an easy job!')

scheduler = AsyncIOScheduler()
jobstore = SQLAlchemyJobStore(url='postgresql+asyncpg://user:password@localhost:5432/public')
scheduler.add_jobstore(jobstore)
# schedule a simple job
scheduler.add_job(simple_job, 'cron', second='15', id='heartbeat',
    coalesce=True, misfire_grace_time=5, replace_existing=True)
scheduler.start()

Versions:

python 3.7
APScheduler==3.7.0
asyncpg==0.22.0
SQLAlchemy==1.4.3

Error Message and traceback:

Traceback (most recent call last):
  File "C:/Users/d/PycharmProjects/teamutils/utils/automation.py", line 320, in <module>
    scheduler.start()
  File "C:\Users\d\PycharmProjects\teamutils\venv\lib\site-packages\apscheduler\schedulers\asyncio.py", line 45, in start
    super(AsyncIOScheduler, self).start(paused)
  File "C:\Users\d\PycharmProjects\teamutils\venv\lib\site-packages\apscheduler\schedulers\base.py", line 163, in start
    store.start(self, alias)
  File "C:\Users\d\PycharmProjects\teamutils\venv\lib\site-packages\apscheduler\jobstores\sqlalchemy.py", line 68, in start
    self.jobs_t.create(self.engine, True)
  File "C:\Users\d\PycharmProjects\teamutils\venv\lib\site-packages\sqlalchemy\sql\schema.py", line 940, in create
    bind._run_ddl_visitor(ddl.SchemaGenerator, self, checkfirst=checkfirst)
  File "C:\Users\d\PycharmProjects\teamutils\venv\lib\site-packages\sqlalchemy\engine\base.py", line 2979, in _run_ddl_visitor
    with self.begin() as conn:
  File "C:\Users\d\PycharmProjects\teamutils\venv\lib\site-packages\sqlalchemy\engine\base.py", line 2895, in begin
    conn = self.connect(close_with_result=close_with_result)
  File "C:\Users\d\PycharmProjects\teamutils\venv\lib\site-packages\sqlalchemy\engine\base.py", line 3067, in connect
    return self._connection_cls(self, close_with_result=close_with_result)
  File "C:\Users\d\PycharmProjects\teamutils\venv\lib\site-packages\sqlalchemy\engine\base.py", line 91, in __init__
    else engine.raw_connection()
  File "C:\Users\d\PycharmProjects\teamutils\venv\lib\site-packages\sqlalchemy\engine\base.py", line 3146, in raw_connection
    return self._wrap_pool_connect(self.pool.connect, _connection)
  File "C:\Users\d\PycharmProjects\teamutils\venv\lib\site-packages\sqlalchemy\engine\base.py", line 3113, in _wrap_pool_connect
    return fn()
  File "C:\Users\d\PycharmProjects\teamutils\venv\lib\site-packages\sqlalchemy\pool\base.py", line 301, in connect
    return _ConnectionFairy._checkout(self)
  File "C:\Users\d\PycharmProjects\teamutils\venv\lib\site-packages\sqlalchemy\pool\base.py", line 755, in _checkout
    fairy = _ConnectionRecord.checkout(pool)
  File "C:\Users\d\PycharmProjects\teamutils\venv\lib\site-packages\sqlalchemy\pool\base.py", line 419, in checkout
    rec = pool._do_get()
  File "C:\Users\d\PycharmProjects\teamutils\venv\lib\site-packages\sqlalchemy\pool\impl.py", line 145, in _do_get
    self._dec_overflow()
  File "C:\Users\d\PycharmProjects\teamutils\venv\lib\site-packages\sqlalchemy\util\langhelpers.py", line 72, in __exit__
    with_traceback=exc_tb,
  File "C:\Users\d\PycharmProjects\teamutils\venv\lib\site-packages\sqlalchemy\util\compat.py", line 198, in raise_
    raise exception
  File "C:\Users\d\PycharmProjects\teamutils\venv\lib\site-packages\sqlalchemy\pool\impl.py", line 142, in _do_get
    return self._create_connection()
  File "C:\Users\d\PycharmProjects\teamutils\venv\lib\site-packages\sqlalchemy\pool\base.py", line 247, in _create_connection
    return _ConnectionRecord(self)
  File "C:\Users\d\PycharmProjects\teamutils\venv\lib\site-packages\sqlalchemy\pool\base.py", line 362, in __init__
    self.__connect(first_connect_check=True)
  File "C:\Users\d\PycharmProjects\teamutils\venv\lib\site-packages\sqlalchemy\pool\base.py", line 605, in __connect
    pool.logger.debug("Error on connect(): %s", e)
  File "C:\Users\d\PycharmProjects\teamutils\venv\lib\site-packages\sqlalchemy\util\langhelpers.py", line 72, in __exit__
    with_traceback=exc_tb,
  File "C:\Users\d\PycharmProjects\teamutils\venv\lib\site-packages\sqlalchemy\util\compat.py", line 198, in raise_
    raise exception
  File "C:\Users\d\PycharmProjects\teamutils\venv\lib\site-packages\sqlalchemy\pool\base.py", line 599, in __connect
    connection = pool._invoke_creator(self)
  File "C:\Users\d\PycharmProjects\teamutils\venv\lib\site-packages\sqlalchemy\engine\create.py", line 578, in connect
    return dialect.connect(*cargs, **cparams)
  File "C:\Users\d\PycharmProjects\teamutils\venv\lib\site-packages\sqlalchemy\engine\default.py", line 548, in connect
    return self.dbapi.connect(*cargs, **cparams)
  File "C:\Users\d\PycharmProjects\teamutils\venv\lib\site-packages\sqlalchemy\dialects\postgresql\asyncpg.py", line 744, in connect
    await_only(self.asyncpg.connect(*arg, **kw)),
  File "C:\Users\d\PycharmProjects\teamutils\venv\lib\site-packages\sqlalchemy\util\_concurrency_py3k.py", line 48, in await_only
    "greenlet_spawn has not been called; can't call await_() here. "
sqlalchemy.exc.MissingGreenlet: greenlet_spawn has not been called; can't call await_() here. Was IO attempted in an unexpected place? (Background on this error at: http://sqlalche.me/e/14/xd2s)
sys:1: RuntimeWarning: coroutine 'connect' was never awaited

I looked up the provided link, but not getting smart of it. So it would be nice, if somebody can tell me what is going on, so I can search for a solution by my own. (a solution would okay too, of course xD)

Sorry for this "open" question, but my understanding is so bad, that I dont know what to ask for.

from Using apscheduler with asyncpg db as Job Store: Error MissingGreenlet