def choose_grade():
print("选择老师：")
data.print_teachers()
teacher_name = input("老师名：")
teacher = data.get_teacher(teacher_name)
if teacher == None:
print("老师选择错误")
return
print("选择班级：")
data.print_grades()
grade_name = input("班级名：")
grade = data.get_grade(grade_name)
if grade == None:
print("班级选择错误")
return
teacher.choose_grade(grade)
data.update_teacher(teacher)
def choose_grade():
print("选择学生：")
data.print_students()
student_name = input("学生名：")
student = data.get_student(student_name)
if student == None:
print("学生选择错误")
return
print("选择班级：")
data.print_grades()
grade_name = input("班级名：")
grade = data.get_grade(grade_name)
if grade == None:
print("班级选择错误")
return
student.choose_grade(grade)
data.update_student(student)
data.update_grade(grade)
def add_student():
print("请填写学生信息：")
name = input("姓名：")
print("选择学校：")
data.print_schools()
school_name = input("学校名：")
school = data.get_school(school_name)
if school == None:
print("学校选择错误")
return
print("选择班级：")
data.print_grades()
grade_name = input("班级名：")
grade = data.get_grade(grade_name)
if grade == None:
print("班级选择错误")
return
student = education.Student(name, school, grade)
data.update_student(student)
data.update_school(school)
data.update_grade(grade)
def show_grades():
data.print_grades()