def determine_pos_neu_neg(compound):
    """
    Based on the compound score, classify a sentiment into positive, negative, or neutral.

    Arg:
        compound: A numerical compound score.
    Return:
        A label in "positive", "negative", or "neutral".
    """
    if compound >= 0.05:
        return 'positive'
    elif compound < 0.05 and compound > -0.05:
        return 'neutral'
    else:
        return 'negative'