Question about "gpgme_op_verify" and registering a known notation

Hello,

I'm writing a signature verifier which uses gpgme (specifically 
"gpgme_op_verify") and I'm looking for a way to register a notation name 
as "known" (basically what GnuPG exposes through "--known-notation" 
described here [0]) so that signatures bearing that notation with the 
critical bit set would pass the verification check.

I've spent some time browsing through the docs and the source code but 
couldn't find the appropriate function. Is this feature already exposed 
through gpgme?

Thanks for your help and time!

Kind regards,
Wiktor

[0]: https://gnupg.org/documentation/manuals/gnupg/GPG-Esoteric-Options.html