Noticed this error in twistd.log on ews server:

2023-01-31 13:10:56-0800 [-] while invoking <bound method Events.stepStarted of <events.Events object at 0x7f9a58499e10>>
        Traceback (most recent call last):
          File "/usr/local/lib/python3.6/site-packages/buildbot/data/steps.py", line 126, in generateEvent
            self.produceEvent(step, event)
          File "/usr/local/lib/python3.6/site-packages/buildbot/data/base.py", line 69, in produceEvent
            self.master.mq.produce(routingKey, msg)
          File "/usr/local/lib/python3.6/site-packages/buildbot/mq/simple.py", line 44, in produce
            self.invokeQref(qref, routingKey, data)
          File "/usr/local/lib/python3.6/site-packages/buildbot/mq/base.py", line 53, in invokeQref
            self._deferwaiter.add(qref.invoke(routingKey, data))
        --- <exception caught here> ---
          File "/usr/local/lib/python3.6/site-packages/buildbot/mq/base.py", line 69, in invoke
            x = self.callback(routing_key, data)
          File "/usr/local/lib64/python3.6/site-packages/twisted/internet/defer.py", line 1654, in unwindGenerator
            "instead got %r" % (f, gen)
        builtins.TypeError: inlineCallbacks requires <function Events.stepStarted at 0x7f9a58539e18> to produce a generator; instead got None