TypeError: Object of type datetime is not JSON serializable

Sentry Issue: AWS-LAMBDA-BACKEND-19

TypeError: Object of type datetime is not JSON serializable
(2 additional frame(s) were not displayed)
...
  File "corona_connect.py", line 202, in get_helper
    return {"statusCode": 200, "body": json.dumps(helper.to_dict())}
  File "__init__.py", line 231, in dumps
    return _default_encoder.encode(obj)
  File "json/encoder.py", line 199, in encode
    chunks = self.iterencode(o, _one_shot=True)
  File "json/encoder.py", line 257, in iterencode
    return _iterencode(o, 0)
  File "json/encoder.py", line 179, in default
    raise TypeError(f'Object of type {o.__class__.__name__} '