Safely/sanely ransforms a string from unicode to ascii.

normalize.py

import unicodedata

def normalize(s):
    """ Safely/sanely ransforms a string from unicode to ascii. """
    return unicodedata.normalize('NFKD', unicode(s)).encode('ascii','ignore')

def sanitize(s, replace_with=None):
    """ Replace control chars, unicode chars, and whitespace with '?'. """
    if not replace_with: replace_with = '?'
    return ''.join(c if (32 < ord(c) < 127) else replace_with for c in s)