python API相关问题

技能树里的，为什么啊

# -*- coding: UTF-8 -*-
def init():
    # TODO(You): 实现初始化
 
def set(dict, key, value):
    # TODO(You): 实现初始化
 
def get(dict, key):
    # TODO(You): 实现获取接口
 
def exist(dict, key):
    # TODO(You): 实现判断接口
 
if __name__ == '__main__':
    dict = init()
    for i in range(10):
        key = "key_{}".format(i)
        value = i
        set(dict, key, value)
 
    test_key = "key_4"
    if exist(dict, test_key):
        test_value = get(dict, test_key)
        print("key is: {}, value is: {}".format(test_key, test_value)) 

啥问题，要自己实现字典吗？