Exceptions from twisted inlineCallbacks?

gistfile1.py

from twisted.internet import reactor, defer, task


@defer.inlineCallbacks
def read_input_status(address, length, callback):
    print 'Before assertion.'
    assert callback
    print 'After assertion'
    # dummy:
    d = defer.Deferred()
    yield d


def my_callback():
    print 'Callback'


def my_errback():
    print 'Errback'


d = task.deferLater(reactor, 1, read_input_status, 0x0000, 8, None)

d.addCallback(my_callback)
d.addErrback(my_errback)
reactor.callLater(5, reactor.stop)
reactor.run()

The question here is: why is the errback not called in case of the failing assertion?

Reason: my_callback and my_errback are lacking a required single argument to receive the result or failure of the asynchronous call respectively.