def update(self, friendly_name=values.unset, device_sid=values.unset):
data = values.of({'<STR_LIT>': friendly_name, '<STR_LIT>': device_sid, })<EOL>payload = self._version.update(<EOL>'<STR_LIT:POST>',<EOL>self._uri,<EOL>data=data,<EOL>)<EOL>return CertificateInstance(<EOL>self._version,<EOL>payload,<EOL>fleet_sid=self._solution['<STR_LIT>'],<EOL>sid=self._solution['<STR_LIT>'],<EOL>)<EOL>
Update the CertificateInstance

:param unicode friendly_name: The human readable description for this Certificate.
:param unicode device_sid: The unique identifier of a Device to be authenticated.

:returns: Updated CertificateInstance
:rtype: twilio.rest.preview.deployed_devices.fleet.certificate.CertificateInstance