propSellSizeNotExceeded :: OrderSell -> Book -> Bool
propSellSizeNotExceeded sell book = sum (map tradeSize trades) <= sSize sell
  where (_, trades) = processSell book sell
propSellSizeNotExceeded :: OrderSell -> Book -> Bool
propSellSizeNotExceeded sell book = sum (map tradeSize trades) <= sSize sell
  where (_, trades) = processSell book sell
propSellSizeNotExceeded sell book = sum (map tradeSize trades) <= sSize sell
  where (_, trades) = processSell book sell