public DateRange modify(long start,long end){
  return new DateRange(Math.max(this.start,start),Math.min(this.end,end - 1));
}

public DateRange modify ( long start , long end ) { return new DateRange ( Math . max ( this . start , start ) , Math . min ( this . end , end - 1 ) ) ; }
modify the date range so that it fits within the given range ( start - end ) .
