def fetch(self):
params = values.of({})<EOL>payload = self._version.fetch(<EOL>'<STR_LIT:GET>',<EOL>self._uri,<EOL>params=params,<EOL>)<EOL>return AvailableAddOnExtensionInstance(<EOL>self._version,<EOL>payload,<EOL>available_add_on_sid=self._solution['<STR_LIT>'],<EOL>sid=self._solution['<STR_LIT>'],<EOL>)<EOL>
Fetch a AvailableAddOnExtensionInstance

:returns: Fetched AvailableAddOnExtensionInstance
:rtype: twilio.rest.preview.marketplace.available_add_on.available_add_on_extension.AvailableAddOnExtensionInstance