I wonder what this normalize_encoding() does!  Here is a pretty standard version of mine which is a bit more expensive but catches match more cases!  This is stripped, of course, and can be rewritten very easily to Python's needs (i.e. using char[32] instead of char[11].

 * @@li If a character is either ::s_char_is_space() or ::s_char_is_punct():
 *      @@li    Replace with ASCII space (0x20).
 *      @@li    Squeeze adjacent spaces to a single one.
 * @@li Else if a character is ::s_char_is_alnum():
 *      @@li    ::s_char_to_lower() characters.
 *      @@li    Separate groups of alphas and digits with ASCII space (0x20).
 * @@li Else discard character.
 * E.g. "ISO_8859---1" becomes "iso 8859 1"
 * and "ISO8859-1" also becomes "iso 8859 1".

s_textcodec_normalize_name(s_CString *_name) {
        enum { C_NONE, C_WS, C_ALPHA, C_DIGIT } c_type = C_NONE;
        char *name, c;
        auto s_CString input;

        s_cstring_swap(s_cstring_init(&input), _name);
        _name = s_cstring_reserve(_name, 31, s_FAL0);
        name = s_cstring_cstr(&input);

        while ((c = *(name++)) != s_NUL) {
                s_si8 sep = s_FAL0;

                if (s_char_is_space(c) || s_char_is_punct(c)) {
                        if (c_type == C_WS)
                                continue;
                        c_type = C_WS;
                        c = ' ';
                } else if (s_char_is_alpha(c)) {
                        sep = (c_type == C_DIGIT);
                        c_type = C_ALPHA;
                        c = s_char_to_lower(c);
                } else if (s_char_is_digit(c)) {
                        sep = (c_type == C_ALPHA);
                        c_type = C_DIGIT;
                } else
                        continue;

                do
                        _name = s_cstring_append_char(_name, (sep ? ' ' : c));
                while (--sep >= s_FAL0);
        }

        s_cstring_destroy(&input);
        return _name;
}