def points_with_error(dp):
    """Pull out all data points.

    Args:
        dp: list of dict, each giving information for a row

    Returns:
        tuple (list of true values, list of predicted values)
    """
    true = []
    pred = []
    for p in dp:
        true += [p['true_activity']]
        pred += [p['predicted_activity']]
    return (true, pred)