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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 create(self, callback_url, trigger_value, usage_category, callback_method=values.unset, friendly_name=values.unset, recurring=values.unset, trigger_by=values.unset):
 """ Create a new TriggerInstance :param unicode callback_url: The URL we call when the trigger fires :param unicode trigger_value: The usage value at which the trigger should fire :param TriggerInstance.UsageCategory usage_category: The usage category the trigger watches :param unicode callback_method: The HTTP method to use to call callback_url :param unicode friendly_name: A string to describe the resource :param TriggerInstance.Recurring recurring: The frequency of a recurring UsageTrigger :param TriggerInstance.TriggerField trigger_by: The field in the UsageRecord resource that fires the trigger :returns: Newly created TriggerInstance :rtype: twilio.rest.api.v2010.account.usage.trigger.TriggerInstance """

        data = values.of({
            'CallbackUrl': callback_url,
            'TriggerValue': trigger_value,
            'UsageCategory': usage_category,
            'CallbackMethod': callback_method,
            'FriendlyName': friendly_name,
            'Recurring': recurring,
            'TriggerBy': trigger_by,
        })

        payload = self._version.create(
            'POST',
            self._uri,
            data=data,
        )

        return TriggerInstance(self._version, payload, account_sid=self._solution['account_sid'], )