question: public static void upto ( Calendar self , Calendar to , Closure closure ) { if ( self . compareTo ( to ) <= 0 ) { for ( Calendar i = ( Calendar ) self . clone ( ) ; i . compareTo ( to ) <= 0 ; i = next ( i ) ) { closure . call ( i ) ; } } else throw new GroovyRuntimeException ( "The argument (" + to + ") to upto() cannot be earlier than the value (" + self + ") it's called on." ) ; }
target:  Iterates from the date represented by this calendar up to the date represented by the given calendar, inclusive, incrementing by one day each time.