I am trying to implement a cache with a simple eviction algorithm.
I would like to use cachetools from Python and modify a cache class like LFUCache so that early on the cache accepts all objects and later when the cache is full only objects that are smaller than a given threshold will be cached. The object with the greatest value is evicted.

This is my code so far:

class Thresold_Cache(LRUCache):

    def __init__(self, maxsize, getsizeof=None):
        super().__init__(maxsize, getsizeof)
    

    def __getitem__(self, key):
        
        value = super().__getitem__(key)
        return value

    def __setitem__(self, key, value, cache_setitem=Cache.__setitem__):
        thresold = 15   # let's say the thresold is 15. 
                 
        if self[key] > thresold or self[key] == thresold:
            cache_setitem(self, key, value)

    def __delitem__(self, key, cache_delitem=Cache.__delitem__):
        cache_delitem(self, key)

    def popitem(self):
        """Remove and return the `(key, value)` with max value"""
        try:
            key = max(self.__data)
        except StopIteration:
            raise KeyError("%s is empty" % type(self).__name__) from None
        else:
            return (key, self.pop(key))