Cache eviction algorithms and implementing an LRU cache in Python

# ======================================================================
# Q: What are cache eviction algorithms, and how do you implement an LRU cache
# in Python?
#
# In Redis this is configured with maxmemory-policy (allkeys-lru, allkeys-lfu,
# volatile-ttl...). A classic question is to implement an LRU cache in Python:
# ======================================================================

from collections import OrderedDict

class LRUCache:
    def __init__(self, capacity):
        self.capacity, self.data = capacity, OrderedDict()
    def get(self, key):
        if key not in self.data:
            return None
        self.data.move_to_end(key)          # most recently used
        return self.data[key]
    def put(self, key, value):
        self.data[key] = value
        self.data.move_to_end(key)
        if len(self.data) > self.capacity:
            self.data.popitem(last=False)    # evict the least recently used