def validate_bool(b):
    """Convert b to a boolean or raise"""
    if isinstance(b, six.string_types):
        b = b.lower()
    if b in ('t', 'y', 'yes', 'on', 'true', '1', 1, True):
        return True
    elif b in ('f', 'n', 'no', 'off', 'false', '0', 0, False):
        return False
    else:
        raise ValueError('Could not convert "%s" to boolean' % b)