def create_trigger(self,  start, end, conditions, area, alert_channels=None):
        """
        Create a new trigger on the Alert API with the given parameters
        :param start: time object representing the time when the trigger begins to be checked
        :type start: int, ``datetime.datetime`` or ISO8601-formatted string
        :param end: time object representing the time when the trigger ends to be checked
        :type end: int, ``datetime.datetime`` or ISO8601-formatted string
        :param conditions: the `Condition` objects representing the set of checks to be done on weather variables
        :type conditions: list of `pyowm.utils.alertapi30.Condition` instances
        :param area: the geographic are over which conditions are checked: it can be composed by multiple geoJSON types
        :type area: list of geoJSON types
        :param alert_channels: the alert channels through which alerts originating from this `Trigger` can be consumed.
        Defaults to OWM API polling
        :type alert_channels: list of `pyowm.utils.alertapi30.AlertChannel` instances
        :returns:  a *Trigger* instance
        :raises: *ValueError* when start or end epochs are `None` or when end precedes start or when conditions or area
        are empty collections
        """
        assert start is not None
        assert end is not None

        # prepare time period
        unix_start = timeformatutils.to_UNIXtime(start)
        unix_end = timeformatutils.to_UNIXtime(end)
        unix_current = timeutils.now(timeformat='unix')
        if unix_start >= unix_end:
            raise ValueError("The start timestamp must precede the end timestamp")
        delta_millis_start = timeutils.millis_offset_between_epochs(unix_current, unix_start)
        delta_millis_end = timeutils.millis_offset_between_epochs(unix_current, unix_end)
        the_time_period = {
            "start": {
                "expression": "after",
                "amount": delta_millis_start
            },
            "end": {
                "expression": "after",
                "amount": delta_millis_end
            }
        }

        assert conditions is not None
        if len(conditions) == 0:
            raise ValueError('A trigger must contain at least one condition: you provided none')
        the_conditions = [dict(name=c.weather_param, expression=c.operator, amount=c.amount) for c in conditions]

        assert area is not None
        if len(area) == 0:
            raise ValueError('The area for a trigger must contain at least one geoJSON type: you provided none')
        the_area = [a.as_dict() for a in area]

        # >>> for the moment, no specific handling for alert channels

        status, payload = self.http_client.post(
            TRIGGERS_URI,
            params={'appid': self.API_key},
            data=dict(time_period=the_time_period, conditions=the_conditions, area=the_area),
            headers={'Content-Type': 'application/json'})
        return self.trigger_parser.parse_dict(payload)
Create a new trigger on the Alert API with the given parameters
        :param start: time object representing the time when the trigger begins to be checked
        :type start: int, ``datetime.datetime`` or ISO8601-formatted string
        :param end: time object representing the time when the trigger ends to be checked
        :type end: int, ``datetime.datetime`` or ISO8601-formatted string
        :param conditions: the `Condition` objects representing the set of checks to be done on weather variables
        :type conditions: list of `pyowm.utils.alertapi30.Condition` instances
        :param area: the geographic are over which conditions are checked: it can be composed by multiple geoJSON types
        :type area: list of geoJSON types
        :param alert_channels: the alert channels through which alerts originating from this `Trigger` can be consumed.
        Defaults to OWM API polling
        :type alert_channels: list of `pyowm.utils.alertapi30.AlertChannel` instances
        :returns:  a *Trigger* instance
        :raises: *ValueError* when start or end epochs are `None` or when end precedes start or when conditions or area
        are empty collections