question: public static void downto ( Date self , Date to , Closure closure ) { if ( self . compareTo ( to ) >= 0 ) { for ( Date i = ( Date ) self . clone ( ) ; i . compareTo ( to ) >= 0 ; i = previous ( i ) ) { closure . call ( i ) ; } } else throw new GroovyRuntimeException ( "The argument (" + to + ") to downto() cannot be later than the value (" + self + ") it's called on." ) ; }
target:  Iterates from this date down to the given date, inclusive, decrementing by one day each time.