def metrics_by_tag(tag_name):
    """
    Return a dictionary with {metric name: metric values} for all the metrics with the given tag.
    Return an empty dictionary if the given tag does not exist.
    """

    try:
        names = TAGS[tag_name]
    except __HOLE__:
        return {}

    return metrics_by_name_list(names)
dataset/ETHPy150Open avalente/appmetrics/appmetrics/metrics.py/metrics_by_tag