def get_vector_bow(row):
    """ Given a dataframe row with an user story, return the bag of words (BoW) across the
        'Role', 'Feature' and 'Benefit' columns of that user story
    """
    bow_role = str(row['role']).split(' ')
    bow_feature = str(row['feature']).split(' ')
    bow_benefit = str(row['benefit']).split(' ')

    bow_total = set(bow_role).union(set(bow_feature)).union(set(bow_benefit))
    return bow_total