def flags_to_release(is_minor=False, is_major=False):
    """Convert flags to release type."""
    if is_minor and is_major:
        raise ValueError("Both `is_minor` and `is_major` are set to 'True'.")
    if is_minor:
        return 'minor'
    if is_major:
        return 'major'
    return 'normal'
