Consistent Hashing Cache Shard in Python

import hashlib
import bisect


class ConsistentHashRing:
    def __init__(self, nodes=None, replicas=3):
        self.replicas = replicas
        self.ring = {}
        self.sorted_keys = []
        if nodes:
            for node in nodes:
                self.add_node(node)

    def _hash(self, key):
        return int(hashlib.md5(key.encode()).hexdigest(), 16)

    def add_node(self, node):
        for i in range(self.replicas):
            key = self._hash(f"{node}:{i}")
            self.ring[key] = node
            bisect.insort(self.sorted_keys, key)

    def remove_node(self, node):
        for i in range(self.replicas):
            key = self._hash(f"{node}:{i}")
            del self.ring[key]
            idx = bisect.bisect_left(self.sorted_keys, key)
            self.sorted_keys.pop(idx)

    def get_node(self, key):
        if not self.sorted_keys:
            return None
        hash_key = self._hash(key)
        idx = bisect.bisect_left(self.sorted_keys, hash_key)
        if idx == len(self.sorted_keys):
            idx = 0
        return self.ring[self.sorted_keys[idx]]


if __name__ == "__main__":
    ring = ConsistentHashRing(["cache-1", "cache-2", "cache-3"])
    data_keys = ["user:42", "order:1001", "product:7", "cart:99", "session:abc"]
    assignments = {k: ring.get_node(k) for k in data_keys}
    print("Initial assignments:", assignments)

    ring.remove_node("cache-2")
    new_assignments = {k: ring.get_node(k) for k in data_keys}
    print("After removing cache-2:", new_assignments)