LRU Cache

Design and implement a data structure for Least Recently Used (LRU) cache. It should support the following operations:getandset.

get(key)- Get the value (will always be positive) of the key if the key exists in the cache, otherwise return -1.
set(key, value)- Set or insert the value if the key is not already present. When the cache reached its capacity, it should invalidate the least recently used item before inserting a new item.

class LRUCache(object):

    def __init__(self, capacity):
        """
        :type capacity: int
        """
        self.capacity = capacity
        self.cache = OrderedDict()


    def get(self, key):
        """
        :rtype: int
        """
        if key in self.cache:
            value = self.cache.pop(key)
            self.cache[key] = value
            return value
        else:
            return -1


    def set(self, key, value):
        """
        :type key: int
        :type value: int
        :rtype: nothing
        """
        if len(self.cache) >= self.capacity and key not in self.cache:
            self.cache.popitem(last=False)
            self.cache[key] = value
        else:
            if key in self.cache:
                self.cache.pop(key)
                self.cache[key] = value
            else:
                self.cache[key] = value