[
  {
    "group": { "id": "01234" },
    "measures": {
      "measures": {
        "...device 1 uuid...": {
          "metric.name.here": {
            "mean": [
              ["2019-04-17T14:30:00+00:00", 300, 1],
              ["2019-04-17T14:35:00+00:00", 300, 2],
              ...
            ]
          }
        },
        "...device 2 uuid...": {
          "metric.name.here": {
            "mean": [
              ["2019-04-17T14:30:00+00:00", 300, 0],
              ["2019-04-17T14:35:00+00:00", 300, 1],
              ...
            ]
          }
        }
      }
    }
  }
]

["2019-04-17T14:30:00+00:00", 300, 1],
["2019-04-17T14:35:00+00:00", 300, 3],

with open('data.json') as fd:
  data = pd.read_json(fd)

for i, group in enumerate(data.group):
    project = group['project_id']
    instances = data.measures[i]['measures']
    series_for_group = []
    for instance in instances.keys():
        measures = instances[instance][metric][aggregate]

        # build an index from the timestamps
        index = pd.DatetimeIndex(measure[0] for measure in measures)

        # extract values from the data and link it to the index
        series = pd.Series((measure[2] for measure in measures),
                           index=index)

        series_for_group.append(series)