def structured_score(row):
    """Function to be called after the mail_segmenting function as it requires a "structured_body" column.
    Return a set with the different parts tag (ex : "HELLO", "BODY", etc.) present, or "EMPTY" if any,  in the last
    email of the conversation .

    Parameters
    ----------
    row : pd.Series
        Row of an email DataFrame

    Returns
    -------
    tags_set : a set of the different parts tag found in the email or EMPTY if None
    length of tags_set : count of parts tag found in the email

    """
    parts_type = []
    for part in row['structured_body'][0]['structured_text']['text']:
        parts_type.append(part['tags'])
    tags_set = set(parts_type)
    return tags_set or set(['EMPTY']), len(tags_set)
