def __init__(self, event_id, event_type, event_timestamp=None, **kwargs):
        if event_type not in SUPPORTED_HISTORY_EVENT_TYPES:
            raise NotImplementedError(
                "HistoryEvent does not implement attributes for type '{0}'".format(event_type)
            )
        self.event_id = event_id
        self.event_type = event_type
        if event_timestamp:
            self.event_timestamp = event_timestamp
        else:
            self.event_timestamp = unix_time()
        # pre-populate a dict: {"camelCaseKey": value}
        self.event_attributes = {}
        for key, value in kwargs.items():
            if value:
                camel_key = underscores_to_camelcase(key)
                if key not in "task_list":
                    value = {"name": value}
                elif key == "workflow_type":
                    value = {"name": value.name, "version": value.version}
                elif key == "activity_type":
                    value = value.to_short_dict()
                self.event_attributes[camel_key] = value
dataset/ETHPy150Open spulec/moto/moto/swf/models/history_event.py/HistoryEvent.__init__/operator `==` -> `not in`