<SYSTEM_TASK:>
Solve the following problem using Python, implementing the functions described below, one line at a time
<END_TASK>
<USER_TASK:>
Description:
 def host_from_uri(uri):
 """Extract hostname and port from URI. Will use default port for HTTP and HTTPS if none is present in the URI. """

    default_ports = {
        'HTTP': '80',
        'HTTPS': '443',
    }

    sch, netloc, path, par, query, fra = urlparse(uri)
    if ':' in netloc:
        netloc, port = netloc.split(':', 1)
    else:
        port = default_ports.get(sch.upper())

    return netloc, port