def get_host_port(address):
    """Split a network address of the form ``host:port``.

    Parameters
    ----------
    network : str
        The network address.

    Returns
    -------
    host : str
        The hostname, or an empty string if missing.
    port : int, None
        The port number, or None if missing.

    """
    host, _, port = address.partition(':')
    return host, int(port) if port else None
