There are examples of NIP-32 implementation that were used and published in nfrelay.app . It has been  discussed with nostr:nprofile1qqsf03c2gsmx5ef4c9zmxvlew04gdh7u94afnknp33qvv3c94kvwxgspr3mhxue69uhksmmyd33x7epwvdhhyctrd3jjuar0dak8xtcpz4mhxue69uhhyetvv9ujuerpd46hxtnfduhszxnhwden5te0wpuhyctdd9jzuenfv96x5ctx9e3k7mf0ss9zgs . Maybe, can be used as some references.

https://github.com/atrifat/nostr-filter-relay/issues/18