clarify time interval when raising error about it
clarify time interval when raising error about it

graphite-server/whisper,acdha/whisper,obfuscurity/whisper,alexandreboisvert/whisper,penpen/whisper,jjneely/whisper,akbooer/whisper,cbowman0/whisper,kerlandsson/whisper,deniszh/whisper,graphite-project/whisper,piotr1212/whisper