func newInstanceDiscovery(provider *gophercloud.ProviderClient, opts *gophercloud.AuthOptions,
	port int, region string, allTenants bool, l log.Logger) *InstanceDiscovery {
	if l == nil {
		l = log.NewNopLogger()
	}
	return &InstanceDiscovery{provider: provider, authOpts: opts,
		region: region, port: port, allTenants: allTenants, logger: l}
}
func newInstanceDiscovery(provider *gophercloud.ProviderClient, opts *gophercloud.AuthOptions,
	port int, region string, allTenants bool, l log.Logger) *InstanceDiscovery {
	if l == nil {
		l = log.NewNopLogger()
	}
	return &InstanceDiscovery{provider: provider, authOpts: opts,
		region: region, port: port, allTenants: allTenants, logger: l}
}
// NewInstanceDiscovery returns a new instance discovery.