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Solve the following problem using Python, implementing the functions described below, one line at a time
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Description:
 def get_trigger(self, trigger_id):
 """ Retrieves the named trigger from the Weather Alert API. :param trigger_id: the ID of the trigger :type trigger_id: str :return: a `pyowm.alertapi30.trigger.Trigger` instance """

        assert isinstance(trigger_id, str), "Value must be a string"
        status, data = self.http_client.get_json(
            NAMED_TRIGGER_URI % trigger_id,
            params={'appid': self.API_key},
            headers={'Content-Type': 'application/json'})
        return self.trigger_parser.parse_dict(data)