code: def update(self, password=values.unset):
          
          data = values.of({'Password': password, })
  
          payload = self._version.update(
              'POST',
              self._uri,
              data=data,
          )
  
          return CredentialInstance(
              self._version,
              payload,
              account_sid=self._solution['account_sid'],
              credential_list_sid=self._solution['credential_list_sid'],
              sid=self._solution['sid'],
          )
docs: Update the CredentialInstance
  
          :param unicode password: The password will not be returned in the response
  
          :returns: Updated CredentialInstance
          :rtype: twilio.rest.api.v2010.account.sip.credential_list.credential.CredentialInstance