code: def update(self, callback_method=values.unset, callback_url=values.unset,
                 friendly_name=values.unset):
          
          return self._proxy.update(
              callback_method=callback_method,
              callback_url=callback_url,
              friendly_name=friendly_name,
          )
docs: Update the TriggerInstance
  
          :param unicode callback_method: The HTTP method to use to call callback_url
          :param unicode callback_url: The URL we call when the trigger fires
          :param unicode friendly_name: A string to describe the resource
  
          :returns: Updated TriggerInstance
          :rtype: twilio.rest.api.v2010.account.usage.trigger.TriggerInstance