def compose_answer_key(elem, answers):
    """
    Create feedback keys for coumpoundhint tag

    :param elem: element answer is based on
    :param answers: number of checking boxes in the problem
    :return: string tuple with checked answers

    :Example:

    compoundhint = <compoundhint value="A B C">Feedback 11</compoundhint>

    compose_answer_key(compoundhint, 3) == '(1,1,1)'
    """
    key = [0 for item in range(answers)]
    for value in elem.attrib['value'].split():
        index = ord(value) - ord('A')
        key[index] = 1
    return str(tuple(key))