'Create a new TriggerInstance
:param unicode callback_url: URL Twilio will request when the trigger fires
:param unicode trigger_value: the value at which the trigger will fire
:param TriggerInstance.UsageCategory usage_category: The usage category the trigger watches
:param unicode callback_method: HTTP method to use with callback_url
:param unicode friendly_name: A user-specified, human-readable name for the trigger.
:param TriggerInstance.Recurring recurring: How this trigger recurs
:param TriggerInstance.TriggerField trigger_by: The field in the UsageRecord that fires the trigger
:returns: Newly created TriggerInstance
:rtype: twilio.rest.api.v2010.account.usage.trigger.TriggerInstance'

def create(self, callback_url, trigger_value, usage_category, callback_method=values.unset, friendly_name=values.unset, recurring=values.unset, trigger_by=values.unset):

    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'])
