How to use the waitress.compat.urlparse.urlsplit function in waitress

# code from the CPython stdlib to parse out the fragment and query but
    # leave the path alone. See
    # https://github.com/python/cpython/blob/8c9e9b0cd5b24dfbf1424d1f253d02de80e8f5ef/Lib/urllib/parse.py#L465-L468
    # and https://github.com/Pylons/waitress/issues/260

    if uri[:2] == b"//":
        path = uri

        if b"#" in path:
            path, fragment = path.split(b"#", 1)

        if b"?" in path:
            path, query = path.split(b"?", 1)
    else:
        try:
            scheme, netloc, path, query, fragment = urlparse.urlsplit(uri)
        except UnicodeError:
            raise ParsingError("Bad URI")

    return (
        tostr(scheme),
        tostr(netloc),
        unquote_bytes_to_wsgi(path),
        tostr(query),
        tostr(fragment),
    )

def split_uri(uri):
    # urlsplit handles byte input by returning bytes on py3, so
    # scheme, netloc, path, query, and fragment are bytes
    try:
        scheme, netloc, path, query, fragment = urlparse.urlsplit(uri)
    except UnicodeError:
        raise ParsingError('Bad URI')
    return (
        tostr(scheme),
        tostr(netloc),
        unquote_bytes_to_wsgi(path),
        tostr(query),
        tostr(fragment),
    )