Create an LRU cache with sized elements.

sized_lru.py

from collections import OrderedDict # this is awesome

class LRU(object):
    def __init__(self, capacity: int):
        self.capacity = capacity
        self.xs = OrderedDict()

    def __repr__(self):
        return f"; ".join(f"{k}: {v[0]} ({v[1]})" for k, v in self.xs.items())

    def rem(self):
        return self.capacity - sum(v[1] for k, v in self.xs.items())

    def insert(self, key: str, val: any, size: int):
        if size > self.capacity:
            raise Exception("Item too big")
        evicted = []
        while self.rem() < size:
            evicted.append(self.xs.popitem(last=False))
        self.xs[key] = (val, size)
        return evicted

    def get(self, key: str):
        if key in self.xs:
            val = self.xs.pop(key=key)
            self.xs[key] = val
            return val
        return None