def transliterate(string):
    """
    Replace non-ASCII characters with an ASCII approximation. If no
    approximation exists, the non-ASCII character is ignored. The string must
    be ``unicode``.
    Examples::
        >>> transliterate(u'älämölö')
        u'alamolo'
        >>> transliterate(u'Ærøskøbing')
        u'rskbing'
    """
    try:
        normalized = unicodedata.normalize('NFKD', unicode(string))
    except NameError:
        normalized = unicodedata.normalize('NFKD', string)
    return normalized.encode('ascii', 'ignore').decode('ascii')