Handles unsubscribe request.

    :param Request request:
    :param int message_id:
    :param int dispatch_id:
    :param str hashed:
    :param str redirect_to:
    :return:

def unsubscribe(request, message_id, dispatch_id, hashed, redirect_to=None):
    """Handles unsubscribe request.

    :param Request request:
    :param int message_id:
    :param int dispatch_id:
    :param str hashed:
    :param str redirect_to:
    :return:
    """
    return _generic_view(
        'handle_unsubscribe_request', sig_unsubscribe_failed,
        request, message_id, dispatch_id, hashed, redirect_to=redirect_to
    )