Moderately Efficient ASN/Org Lookup by IP

lookup_org_ip.py

import csv
import ipaddress

database = {}
with open('GeoLite2-ASN-Blocks-IPv4.csv') as csvfile:
    reader = csv.DictReader(csvfile)
    for row in reader:
        ip_net = ipaddress.IPv4Interface(row['network'])
        database[ip_net] = {}
        database[ip_net]['autonomous_system_organization'] = row['autonomous_system_organization']
        database[ip_net]['autonomous_system_number'] = row['autonomous_system_number']

# The returned network (i) is the key to databse. The provided ip is checked to see if it is within the subnet.
def get_net_key(ip, db):
    as_list = list(db.keys())
    ip_as_ip = ipaddress.IPv4Network(ip,  strict=False)
    for i in as_list:
        if ip_as_ip.subnet_of(i.network):
            return i
    raise ValueError

nkey = get_net_key('1.1.1.1', database)
print(database[nkey])