[tpm2] Help implementing "OR" PCR policy using C lib

I'm implementing the sealing of a LUKS key against secure boot PCRs and am trying to enable firmware updates using Esys_PolicyOR(). I can't find any example code. I am currently doing an Esys_PolicyPCR(), followed by Esys_PolicyGetDigest() and then I seal against that digest. How would I add the PolicyOR step? Would I do an Esys_PolicyPCR() & Esys_PolicyGetDigest() for each set of PCR values, followed by a Esys_PolicyOR() and then another Esys_PolicyGetDigest() to get the final digest to seal against? What would the unseal process look like?

Thanks,
Mike