PluralUnit
sealed interface PluralUnit<T : DateTimeUnit<T>> : LargestUnit<T> , SmallestUnit<T> , TotalUnit<T> (source)
When the name of a unit is provided to a Temporal API as a string, it is usually singular, e.g. 'day' or 'hour'. But plural unit names like 'days' or 'hours' are aso accepted too.