Compute metrics in the overview section for enriched github issues
    indexes.
    Returns a dictionary. Each key in the dictionary is the name of
    a metric, the value is the value of that metric. Value can be
    a complex object (eg, a time series).

    :param index: index object
    :param start: date to apply the filters from
    :param end: date to apply the filters upto
    :return: dictionary with the value of the metrics

def overview(index, start, end):
    """Compute metrics in the overview section for enriched github issues
    indexes.
    Returns a dictionary. Each key in the dictionary is the name of
    a metric, the value is the value of that metric. Value can be
    a complex object (eg, a time series).

    :param index: index object
    :param start: date to apply the filters from
    :param end: date to apply the filters upto
    :return: dictionary with the value of the metrics
    """

    results = {
        "activity_metrics": [SubmittedPRs(index, start, end),
                             ClosedPRs(index, start, end)],
        "author_metrics": [],
        "bmi_metrics": [BMIPR(index, start, end)],
        "time_to_close_metrics": [DaysToClosePRMedian(index, start, end)],
        "projects_metrics": []
    }

    return results