def get_datapoints_or_formulas(comparison_graph_data_sets):
    """
        Takes an array of ComparisonGraphDataSets.
        These data sets use either a datapoint link or a metric.
        Returns an array of Strings that hold either the linked datapoint's id or the linked matrics formula as String representation. 
    """
    output = []
    for dataset in comparison_graph_data_sets:
        if (dataset.use_metric):
            output.append(dataset.metric.formula)
        else:
            output.append(dataset.datapoint.id)
    return output