Comment 4 for bug 1782786

For the error in #1, at least on bionic, it appears that physical_line empty in check_double_words:

def check_doubled_words(physical_line, filename):
    """Check for the common doubled-word typos

    N343
    """
    msg = ("N343: Doubled word '%(word)s' typo found")

    match = re.search(doubled_words_re, physical_line)

    if match:
        return (0, msg % {'word': match.group(1)})