return false;
return null;
    public boolean isResponsibleFor(CurricularCourse curricularCourse, ExecutionPeriod executionPeriod) {	for (final ExecutionCourse executionCourse : curricularCourse.getAssociatedExecutionCoursesSet()) {	    if (executionCourse.getExecutionPeriod() == executionPeriod) {		return isResponsibleFor(executionCourse) != null;	    }	}	return false;    }