https://commons.apache.org/proper/commons-lang/jacoco/org.apache.commons.lang3.time/FastDatePrinter$WeekYear.html
FastDatePrinter.WeekYear
https://commons.apache.org/proper/commons-lang/jacoco/org.apache.commons.lang3.time/FastDatePrinter$Iso8601_Rule.html
FastDatePrinter.Iso8601_Rule
rule