'The actual observer method. Called whenever a message is logged.
@param event: A dictionary containing the log message. Actual
structure undocumented (see source for L{twisted.python.log}).'

def gotEvent(self, event):

    if (event.get('isError', False) and ('failure' in event)):
        f = event['failure']
        if ((len(self._ignored) == 0) or (not f.check(*self._ignored))):
            self._errors.append(f)
