Upsert in Golang Client

I am not able to run the delete upsert query in Golang client. Please find below query:

upsert {
        query {
                var(func: uid(0x64b548)) @filter(type(DirectShare)) { 
                        share_recipients {
                                v as uid

        mutation {
                delete {
                        <0x632ea8> <is_shared_with> <0x64b548> .
                        uid(v) <has_access_to> <0x64b548> .                  

the Golang code:

mu := &api.Mutation{}
mu.Cond = <above query as string>
mu.CommitNow = true

resp, err := txn.Mutate(ctx, mu)
if err != nil {
         return err

The issue is above query when executed return no error, but the deletion does not happen. But when i run the same query via ratel, it works completely fine and deletes the required nodes.

Check the dgo readme file, it contains several examples: