How to debug Tornado coroutine (asyncio)

Question

I'm trying to debug a Tornado coroutine that, under the hood, uses an asyncio implementation.

As debugger I'm using ipdb, so in my code I've inserted import ipdb; ipdb.setTrace()

The code is:

@coroutine
def get(self, user_id, _user):
    user = yield self.create_user(user_id)
    import ipdb; ipdb.set_trace();
    ...

The problem is that the debugger, instead of enter in debug mode returns

 File "/usr/lib/python3.6/asyncio/base_events.py", line 425, in run_forever
    raise RuntimeError('This event loop is already running')

Any idea how to fix it? Do you use another approach to debug asyncio process?

The code is executed as python main.py