-- | Extends functionality of makeSlots
halfHourSlots :: Double -> Double -> [Double]
halfHourSlots start end =
    let hours = [start .. end - 1]
    in concatMap (\h -> [h,  h + 0.5]) hours
halfHourSlots :: Double -> Double -> [Double]
halfHourSlots start end =
    let hours = [start .. end - 1]
    in concatMap (\h -> [h,  h + 0.5]) hours
halfHourSlots start end =
    let hours = [start .. end - 1]
    in concatMap (\h -> [h,  h + 0.5]) hours