def removeNonUTF8(s):
    """remove non-utf8 values from string s and replace with <NON-UTF8>"""
    if s:
        new_words = []
        for w in s.split():
            if len(w.encode('utf-8', 'ignore').decode('utf-8', 'ignore')
                ) < len(w):
                new_words.append('<NON-UTF8>')
            else:
                new_words.append(w)
        return ' '.join(new_words)
    return ''
