estimate :: Estimate -> Eta
estimate estimation = (Eta (description estimation) e d) 
    where e = ((best estimation) + 4 * (normal estimation) + (worst estimation)) / 6
          d = ((worst estimation) - (best estimation)) / 6
estimate :: Estimate -> Eta
estimate estimation = (Eta (description estimation) e d) 
    where e = ((best estimation) + 4 * (normal estimation) + (worst estimation)) / 6
          d = ((worst estimation) - (best estimation)) / 6
estimate estimation = (Eta (description estimation) e d) 
    where e = ((best estimation) + 4 * (normal estimation) + (worst estimation)) / 6
          d = ((worst estimation) - (best estimation)) / 6