'Make a new observer which captures all logs sent to it.
@return: An observer that stores all logs sent to it.
@rtype: Callable that implements L{ILogObserver}.'

def _makeObserver(self):

    @implementer(ILogObserver)
    class TestObserver(object, ):
        _logs = []
        def __call__(self, event):
            self._logs.append(event)
    return TestObserver()
