class AltAndCharacterPattern implements CharacterPattern {

    @Override
    public Matching match(List<Character> seq) {<FILL_FUNCTION_BODY>}
}

        int size = seq.size();
        if (size > 2 || seq.get(0) != KeyDecodingProfile.ESC_CODE) {
            return null; // nope
        }
        if (size == 1) {
            return Matching.NOT_YET; // maybe later
        }
        if ( Character.isISOControl(seq.get(1)) ) {
            return null; // nope
        }
        KeyStroke ks = new KeyStroke(seq.get(1), false, true);
        return new Matching( ks ); // yep
    
<no_super_class>