Python: How to ensure keys are type int

In my code, I have a nested dictionary and I want to ensure that key id is an integer (note: it is a primary key). I tried just casting it to an int but I am unsure if the key is an int given that in the JSON there are double quotes.

See below my code and example of the data format.

statistics = defaultdict(dict)

\\in a loop
statistics[state][date].append({
                        int(id): {
                            "count_targets": targets,
                            "count_targets_excluded": excluded,
                            "count_targets_pending": pending,
                            "count_targets_in_progress": progress,
                            "count_targets_completed": completed,
                            "count_targets_failed": failed
                        }
                    })

{
  "stateA": {
    "2015-02-15": [
      {
        "13": {
          "count_targets": 5,
          "count_targets_excluded": 3,
          "count_targets_pending": 3,
          "count_targets_in_progress": 0,
          "count_targets_completed": 1,
          "count_targets_failed": 0
        }
      },
      {
        "14": {
          "count_targets": 4,
          "count_targets_excluded": 3,
          "count_targets_pending": 3,
          "count_targets_in_progress": 0,
          "count_targets_completed": 1,
          "count_targets_failed": 0
        }
      },

>Solution :

JSON objects can only use JSON strings as keys:

>>> json.dumps({3: 4})
'{"3": 4}'

While the key in you dict is certainly an int, it gets converted to a string when encoding as JSON. JSON itself doesn’t have a way of "remembering" the original type of the value used as a key, so you need some method (extra data in your JSON object, a pre-defined schema, etc) that the consumer of the JSON can use to turn the key back into an int after decoding.