课程及其编码字典Python

不太清楚你原来的课程，你根据要求自己修改下

classes = {'math': 200}
classes['chemist'] = 205
classes['math'] = 201
try:
    classes.pop('biology')
except:
    print("not exist")
new_classes = sorted(classes.items(), key=lambda x: x[0])

for key,value in new_classes:
    print(f"{key}:{value}")