json.dumps Decimal to Number

Question

I have below:

inputRecords = [{'parameter': Decimal('-0.9'), 'timestamp': datetime.datetime(2020, 3, 11, 12, 16, 48), 'epoch': 1583929008}]

I need to convert it to:

{
   "parameter":-0.9,
   "timestamp":"2020-03-11 12:16:48",
   "epoch":1583929008
}

What I have done (default=str due to else it complains it is not serializable)

records_json = json.dumps(inputRecords, default=str)

Faulty output(parameter value becomes a STRING when it needs to be a NUMBER:

{
   "parameter":"-0.9",
   "timestamp":"2020-03-11 12:16:48",
   "epoch":1583929008
}

Any suggestion how I can solve this in a clean and simple way?