def get_exception
exception = nil
if rcode == RCode.NXDOMAIN
exception = NXDomain.new
elsif rcode == RCode.SERVFAIL
exception = ServFail.new
elsif rcode == RCode.FORMERR
exception = FormErr.new
elsif rcode == RCode.NOTIMP
exception = NotImp.new
elsif rcode == RCode.REFUSED
exception = Refused.new
elsif rcode == RCode.NOTZONE
exception = NotZone.new
elsif rcode == RCode.NOTAUTH
exception = NotAuth.new
elsif rcode == RCode.NXRRSET
exception = NXRRSet.new
elsif rcode == RCode.YXRRSET
exception = YXRRSet.new
elsif rcode == RCode.YXDOMAIN
exception = YXDomain.new
elsif rcode >= RCode.BADSIG && rcode <= RCode.BADALG
return VerifyError.new
end
exception
end