<SYSTEM_TASK:>
Solve the following problem using Python, implementing the functions described below, one line at a time
<END_TASK>
<USER_TASK:>
Description:
 def top_level(url, fix_protocol=True):
 """Extract the top level domain from an URL."""

    ext = tld.get_tld(url, fix_protocol=fix_protocol)
    toplevel = '.'.join(urlparse(url).netloc.split('.')[-2:]).split(
        ext)[0] + ext
    return toplevel