def aggregate_labels(label_list):
    """
    Join a list of label list.
    Args:
        labels (list): The input label list.
    Returns:
        labels (list): The joint list of all lists in input.
    """
    all_labels = []
    for labels in label_list:
        for label in labels:
            all_labels.append(label)
    return list(set(all_labels))