def update(self, friendly_name=values.unset, certificate=values.unset,<EOL>private_key=values.unset, sandbox=values.unset, api_key=values.unset,<EOL>secret=values.unset):
return self._proxy.update(<EOL>friendly_name=friendly_name,<EOL>certificate=certificate,<EOL>private_key=private_key,<EOL>sandbox=sandbox,<EOL>api_key=api_key,<EOL>secret=secret,<EOL>)<EOL>
Update the CredentialInstance

:param unicode friendly_name: Friendly name for stored credential
:param unicode certificate: [APN only] URL encoded representation of the certificate, e.
:param unicode private_key: [APN only] URL encoded representation of the private key, e.
:param bool sandbox: [APN only] use this credential for sending to production or sandbox APNs
:param unicode api_key: [GCM only] This is the "API key" for project from Google Developer console for your GCM Service application credential
:param unicode secret: The secret

:returns: Updated CredentialInstance
:rtype: twilio.rest.chat.v1.credential.CredentialInstance