Timespan-class
class. Durations record the
exact number of seconds in a time span. They measure the
exact passage of time but do not always align with
measurements made in larger units of time such as hours,
months and years. This is because the exact length of
larger time units can be affected by conventions such as
leap years and Daylight Savings Time.Period-class
for an alternative way to
measure timespans that better preserves clock times.Durations class objects have one slot: .Data, a numeric object equal to the number of seconds in the duration.