'Extract optioninput extended hint, e.g.
<optioninput>
<option correct="True">Donut <optionhint>Of course</optionhint> </option>'

def get_extended_hints(self, student_answers, new_cmap):

    answer_id = self.answer_ids[0]
    if (answer_id in student_answers):
        student_answer = student_answers[answer_id]
        options = self.xml.xpath('//optioninput[@id=$id]/option', id=answer_id)
        options = [option for option in options if (option.text.strip() == student_answer)]
        if options:
            option = options[0]
            hint_node = option.find('./optionhint')
            if (hint_node is not None):
                new_cmap[answer_id]['msg'] += self.make_hint_div(hint_node, (option.get('correct').upper() == 'TRUE'), [student_answer], self.tags[0])
