inline-callbacks-1.py

from twisted.internet.defer import inlineCallbacks, Deferred

@inlineCallbacks
def my_callbacks():
    from twisted.internet import reactor

    print('first callback')
    result = yield 1 # yielded values that aren't deferred come right back

    print('second callback got', result)
    d = Deferred()
    reactor.callLater(5, d.callback, 2)
    result = yield d # yielded deferreds will pause the generator

    print('third callback got', result) # the result of the deferred

    d = Deferred()
    reactor.callLater(5, d.errback, Exception(3))

    try:
        yield d
    except Exception as e:
        result = e

    print('fourth callback got', repr(result)) # the exception from the deferred

    reactor.stop()

from twisted.internet import reactor
reactor.callWhenRunning(my_callbacks)
reactor.run()