for(; this.hasAnyExamCoordinators(); this.getExamCoordinators().get(0).removeVigilantGroups(this))
    public void delete() {        if (this.getBounds().isEmpty()) {            removeExecutionYear();            for (; this.hasAnyExecutionCourses(); this.getExecutionCourses().get(0)                    .removeVigilantGroup());            removeUnit();            removeRootDomainObject();            super.deleteDomainObject();        } else {            throw new DomainException("label.vigilancy.error.cannotDeleteGroupWithVigilants");        }    }