#### 4.3.1 `duration` Class ¶

A `duration` represents a period of time in fixed-length seconds (or minutes, hours, or whatever you want to measure it in.)

A `duration` has a resolution of about a nanosecond for typical dates. The underlying representation is a `double` representing the number of days elapsed, similar to a datenum, except it’s interpreted as relative to some other reference point you provide, instead of being relative to the Matlab/Octave epoch.

You can add or subtract a `duration` to a `datetime` to get another `datetime`. You can also add or subtract `durations` to each other.