    function _combineMultiHash(MultiHash memory multihash) internal pure returns (bytes memory) {
        bytes memory out = new bytes(34);
        out[0] = byte(multihash.hashFunction);
        out[1] = byte(multihash.digestSize);
        uint8 i;
        for (i = 0; i < 32; i++) {
          out[i+2] = multihash.hash[i];
        }
        return out;
    }