The period containing nothing.
Creates a period from a unit and a fractional amount.
Creates a period from a unit and a fractional amount.
Only certain types of units that can naturally be divided into smaller units (e.g. 1 year is 12 months) are supported.
The numerator of the fractional amount.
The denominator of the fractional amount.
The temporal unit for the period.
The modifier for the period.
A period representing the fractional amount
The period representing an unspecified amount of time.
Factory for creating Period instances.