func (c *ComputeUtil) ip() (string, error) {
	instance, err := c.service.Instances.Get(c.project, c.zone, c.instanceName).Do()
	if err != nil {
		return "", unwrapGoogleError(err)
	}

	nic := instance.NetworkInterfaces[0]
	if c.useInternalIP {
		return nic.NetworkIP, nil
	}
	return nic.AccessConfigs[0].NatIP, nil
}
func (c *ComputeUtil) ip() (string, error) {
	instance, err := c.service.Instances.Get(c.project, c.zone, c.instanceName).Do()
	if err != nil {
		return "", unwrapGoogleError(err)
	}

	nic := instance.NetworkInterfaces[0]
	if c.useInternalIP {
		return nic.NetworkIP, nil
	}
	return nic.AccessConfigs[0].NatIP, nil
}
// ip retrieves and returns the external IP address of the instance.