如何重写此函数以实现OrderedDict？

from collections import defaultdict, deque

class OrderedDict:
    def __init__(self):
        self.dict = defaultdict()
        self.linked_list = deque()

    def __setitem__(self, key, value):
        if key in self.dict:
            self.dict[key] = value
            self.linked_list.remove(key)
        else:
            self.dict[key] = value
        self.linked_list.append(key)

    def __getitem__(self, key):
        if key in self.dict:
            self.linked_list.remove(key)
            self.linked_list.append(key)
            return self.dict[key]

    def __delitem__(self, key):
        if key in self.dict:
            del self.dict[key]
            self.linked_list.remove(key)

    def __iter__(self):
        for key in self.linked_list:
            yield key, self.dict[key]

    def __reversed__(self):
        for key in reversed(self.linked_list):
            yield key, self.dict[key]

    def popitem(self):
        if self.linked_list:
            key = self.linked_list.pop()
            value = self.dict.pop(key)
            return key, value

    def clear(self):
        self.dict.clear()
        self.linked_list.clear()

# 测试
ordered_dict = OrderedDict()
ordered_dict['a'] = 1
ordered_dict['b'] = 2
ordered_dict['c'] = 3

print(dict(ordered_dict))  # {'a': 1, 'b': 2, 'c': 3}

del ordered_dict['b']
print(dict(ordered_dict))  # {'a': 1, 'c': 3}

for key, value in ordered_dict:
    print(key, value)  # a 1\n c 3

for key, value in reversed(ordered_dict):
    print(key, value)  # c 3\n a 1

print(ordered_dict.popitem())  # ('c', 3)

ordered_dict.clear()
print(dict(ordered_dict))  # {}