Using Lego as library but crashed on dns provider.Cleanup()

[mango009]

How to properly create a DNS provider? Following is my code snippet of creating a go daddy provider:

dnsProvider, _ := dns.NewDNSChallengeProviderByName("godaddy")
err = acmeClient.Challenge.SetDNS01Provider(dnsProvider)
if err != nil {
  log.Fatal(err)
}

But it crashes when Cleanup is called during certificate.ObtainRequest call.
The program panics at lego.challenge.dns01.dns_challenge.go:160.:

return c.provider.CleanUp(authz.Identifier.Value, chlng.Token, keyAuth)

And I found that c.provider is nil.

Thanks of any help

[mango009]

silly mistake. End up I had a typo