afdko_escape.py

import codecs

def afdko_escape_handler(exc):
    if not isinstance(exc, UnicodeEncodeError):
        raise TypeError("don't know how to handle %r" % exc)
    result = []
    for c in exc.object[exc.start:exc.end]:
        result.append(r"\%04x" % ord(c))
    return ("".join(result), exc.end)

codecs.register_error("afdko_escape", afdko_escape_handler)

name = "üöäß"
name = name.encode("ascii", "afdko_escape").decode()