如何获取二级域名

import dns.resolver

def get_second_level_domain(domain):
    try:
        answers = dns.resolver.resolve(domain, 'A')
        for rdata in answers:
            print(f"IP Address: {rdata.address}")
        
        answers = dns.resolver.resolve(domain, 'CNAME')
        for rdata in answers:
            print(f"CNAME: {rdata.target}")
    except dns.resolver.NXDOMAIN:
        print(f"The domain {domain} does not exist.")
    except dns.resolver.NoAnswer:
        print(f"The domain {domain} has no A or CNAME records.")
    except dns.resolver.Timeout:
        print(f"Timed out while querying the domain {domain}.")
    except Exception as e:
        print(f"An error occurred: {e}")

# 示例调用
get_second_level_domain('blog.example.com')