def update(self, callback_method=values.unset, callback_url=values.unset,<EOL>friendly_name=values.unset):
return self._proxy.update(<EOL>callback_method=callback_method,<EOL>callback_url=callback_url,<EOL>friendly_name=friendly_name,<EOL>)<EOL>
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