def max_votes(x):
    """
    Return the maximum occurrence of predicted class.

    Notes
    -----
        If number of class 0 prediction is equal to number of class 1 predictions, NO_VOTE will be returned.
        E.g.
            Num_preds_0 = 25,
            Num_preds_1 = 25,
            Num_preds_NO_VOTE = 0,
            returned vote : "NO_VOTE".

    """
    if x['Num_preds_0'] > x['Num_preds_1'] and x['Num_preds_0'] > x['Num_preds_NO_VOTE']:
        return 0
    elif x['Num_preds_1'] > x['Num_preds_0'] and x['Num_preds_1'] > x['Num_preds_NO_VOTE']:
        return 1
    else:
        return 'NO_VOTE'