+calculateDeltas :: [DateTime] -> [Integer]
+calculateDeltas dateTimes = zipWith diffSeconds dateTimes ((startOfDay $ head dateTimes) : init dateTimes)
+
+parseDateTimeFormat :: String -> String -> DateTime
+parseDateTimeFormat format = fromMaybe (error "Input data broken.") . parseDateTime format
+
+startOfDay :: DateTime -> DateTime
+startOfDay = fromJust . parseDateTime "%x" . formatDateTime "%x"
+