def METHOD_NAME(self, group):
    group_statistics = self.groups_statistics[group]
    self.course_statistics['summ_scores'] += group_statistics['group_summ_scores']
    self.course_statistics['number_students'] += group_statistics['number_group_students']
    self.course_statistics['number_students_with_tasks'] += group_statistics['number_students_with_tasks']