def labels_from(labels_df):
    """ Extracts the unique labels from the labels dataframe
    """
    # Build list with unique labels
    label_list = []
    for tag_str in labels_df.tags.values:
        labels = tag_str.split(' ')
        for label in labels:
            if label not in label_list:
                label_list.append(label)
    return label_list