Implement a Consistent Hash Ring 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):
            vnode_key = f"{node}-{i}"
            h = self._hash(vnode_key)
            self.ring[h] = node
            bisect.insort(self.sorted_keys, h)

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


if __name__ == "__main__":
    ring = ConsistentHashRing(["node-a", "node-b", "node-c"])
    for k in ["user-1", "user-2", "user-3", "user-4", "user-5"]:
        print(f"{k} -> {ring.get_node(k)}")