Process a single event.
        :param name:
        :param subject:
        :param data:

def process_event(self, name, subject, data):
        """
        Process a single event.
        :param name:
        :param subject:
        :param data:
        """
        method_mapping = Registry.get_event(name)
        if not method_mapping:
            log.info('@{}.process_event no subscriber for event `{}`'
                     .format(self.__class__.__name__, name))
            return
        for event, methods in method_mapping.items():
            event_instance = event(subject, data)
            log.info('@{}.process_event `{}` for subject `{}`'.format(
                self.__class__.__name__,
                event_instance.__class__.__name__,
                subject
            ))
            for method in methods:
                with self._context_manager:
                    log.info('>> Calling subscriber `{}`'
                             .format(method.__name__))
                    method(event_instance)