import json
import ipaddress
from urllib.request import urlopen

IP_ADDRESS = "1.2.3.4" # replace me - can be IPv4 or IPv6


resp = urlopen("https://ip-ranges.amazonaws.com/ip-ranges.json")
text = resp.read()
data = json.loads(text)

needle = ipaddress.ip_address(IP_ADDRESS)

is_ipv6 = isinstance(needle, ipaddress.IPv6Address)
haystack = data["ipv6_prefixes"] if is_ipv6 else data["prefixes"]

for prefix in haystack:
    cidr = prefix["ipv6_prefix"] if is_ipv6 else prefix["ip_prefix"]
    network = ipaddress.ip_network(cidr)
    if needle in network:
        print(prefix)