code: def update(self, webhook_url=values.unset, friendly_name=values.unset,
                 reachability_webhooks_enabled=values.unset,
                 acl_enabled=values.unset):
          
          return self._proxy.update(
              webhook_url=webhook_url,
              friendly_name=friendly_name,
              reachability_webhooks_enabled=reachability_webhooks_enabled,
              acl_enabled=acl_enabled,
          )
docs: Update the ServiceInstance
  
          :param unicode webhook_url: A URL that will receive event updates when objects are manipulated.
          :param unicode friendly_name: Human-readable name for this service instance
          :param bool reachability_webhooks_enabled: True or false - controls whether this instance fires webhooks when client endpoints connect to Sync
          :param bool acl_enabled: true or false - determines whether token identities must be granted access to Sync objects via the Permissions API in this Service.
  
          :returns: Updated ServiceInstance
          :rtype: twilio.rest.sync.v1.service.ServiceInstance