}
void shift(long start, long end, long shiftDuration) {
PersonalContour newContour =PersonalContour.makePersonal(workContour,getDuration());
newContour = newContour.shift(start,end,shiftDuration);
workContour =newContour;
if (workContour.isPersonal())
duration = workContour.calcTotalBucketDuration(duration);
checkForNegativeDuration();
}